Note: Descriptions are shown in the official language in which they were submitted.
CA 02709513 2010-07-14
ELECTRICAL SWITCHING MODULE
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of Application No. 12/618,497,
filed November
13, 2009, the contents of which are herein incorporated by reference in their
entirety.
BACKGROUND
Electrical switching devices such as relays and circuit breakers can be placed
on a circuit
board with electronics to actuate the electrical switching device. For
example, the circuit board
can include a first set of terminals for line and load wiring. Another set of
terminals can receive
an input for actuation of the relay. However, control electronics, monitoring,
or the like are
implemented on a different circuit board or module.
Electrical switching devices such as relays and circuit breakers are often
encapsulated in
cases to protect the operating mechanisms from dust, moisture and other
environmental
conditions, and to prevent technicians and others from contacting live
electrical parts. Certain
operating conditions may cause a blast or build-up of hot, pressurized gases
and other materials
within the case. For example, short circuits may cause contacts in relays or
circuit breakers to
melt or explode, thereby releasing hot gases and molten metal. As another
example, an over
current condition may cause the contacts in a circuit breaker to open, which
may in turn, create a
momentary arc between the contacts. The arc releases a blast of ionized air.
If the blast is not vented from inside the case, it may damage, destroy or
interfere with the
operation of the electrical device and/or cause the case to rupture, thereby
scattering dangerous
blast products. Thus, cases for electrical switching devices are often
provided with a vent in the
top or side of the case to enable a short circuit or other type of blast to
escape from within the
case. While venting the case may solve certain problems with the electrical
switching device, it
often causes other problems. For example, in an electrical enclosure housing
multiple
components, a blast from one device may be directed at another device, which
in turn is damaged
or destroyed by the blast. In addition, within the electrical switching
device, the blast can short
high voltage terminals with low voltage circuitry, creating a potential
hazard.
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Some other previous efforts to accommodate a blast from an electrical
switching device
have involved the use of complicated systems of baffles or dividers between
components to
direct the blast from one component away from other components. These systems,
however, add
cost and complexity, and may still create hazardous conditions.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 illustrates an embodiment of an electrical switching module according
to some
inventive principles of this patent disclosure.
Fig. 2 illustrates an embodiment of an electrical switching module with a
position sensor
according to some inventive principles of this patent disclosure.
Fig. 3 illustrates an embodiment of an electrical switching module with a zero-
crossing
detector according to some inventive principles of this patent disclosure.
Fig. 4 illustrates an embodiment of an electrical switching module with a
current sensor
according to some inventive principles of this patent disclosure.
Fig. 5 illustrates an embodiment of an electrical switching module with a
voltage sensor
according to some inventive principles of this patent disclosure.
Fig. 6,illustrates an embodiment of an electrical switching module with a
communication
interface according to some inventive principles of this patent disclosure.
Fig. 7 illustrates an embodiment of an electrical switching module with a
dimming
interface according to some inventive principles of this patent disclosure.
Fig. 8 illustrates an analog signal measurement circuit capable of signal
transmission
across a voltage boundary according to some inventive principles of this
patent disclosure.
Fig. 9 illustrates the circuit of Fig. 8 with a zero-crossing detector
according to some
inventive principles of this patent disclosure.
Fig. 10 illustrates a pulse width modulated pulse train synchronized with a
zero-crossing
according to some inventive principles of this patent disclosure.
Fig. 11 illustrates an embodiment of a combined signal measurement circuit and
zero
crossing detector according to some inventive principles of this patent
disclosure.
Fig. 12 illustrates another embodiment of a combined signal measurement
circuit and
zero crossing detector according to some inventive principles of this patent
disclosure.
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Fig. 13 illustrates a circuit spanning a voltage region boundary according to
some
inventive principles of this patent disclosure.
Fig. 14 illustrates a zero-crossing synchronization circuit according to some
inventive
principles of this patent disclosure.
5. Fig. 15 illustrates an example of a timing of an actuation of the
electrical switching
device relative to zero-crossings of a waveform according to some inventive
principles of this
patent disclosure.
Fig. 16 illustrates another zero-crossing synchronization circuit according to
some
inventive principles of this patent disclosure.
Fig. 17 illustrates an example of a measurement of an actuation time of the
electrical
switching device relative to zero-crossings of a waveform according to some
inventive principles
of this patent disclosure.
Fig. 18 illustrates a zero-crossing detector according to some inventive
principles of this
patent disclosure.
Fig. 19 illustrates an example of the pulse generator of Fig. 18 according to
some
inventive principles of this patent disclosure.
Fig. 20 illustrates another example of the pulse generator of Fig. 18
according to some
inventive principles of this patent disclosure.
Fig. 21 illustrates a dimming control circuit according to some inventive
principles of this
patent disclosure.
Fig. 22 illustrates another dimming control circuit according to some
inventive principles
of this patent disclosure.
Fig. 23 illustrates an embodiment of a venting system for an electrical
switching
component according to the inventive principles of this patent disclosure.
Fig. 24A is a front view of another embodiment of a venting system according
to the
inventive principles of this patent disclosure.
Fig. 24B is a cross section taken through line AA of the embodiment of Fig.
24A.
Fig. 25 illustrates an embodiment of a relay according to some inventive
principles of this
patent disclosure.
Fig. 26 illustrates an embodiment of a relay card according to some inventive
principles
of this patent disclosure.
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Fig. 27 is a cross-sectional view illustrating another embodiment of a venting
system
according to some inventive principles of this patent disclosure.
Fig. 28 is a cross-sectional view illustrating another embodiment of a venting
system
according to some inventive principles of this patent disclosure.
Fig. 29 is a cross-sectional view illustrating another embodiment of an
electrical
switching component according to some inventive principles of this patent
disclosure.
Fig. 30 is a partially exploded perspective view illustrating another
embodiment of a
venting system according to some inventive principles of this patent
disclosure.
Fig. 31 is a perspective view showing the opposite side of the embodiment of
Fig. 30.
Fig. 32 is a perspective view illustrating an electrical switching device
according to some
inventive principles of this patent disclosure.
Fig. 33 is a cutaway view illustrating a duct according to some inventive
principles of this
patent disclosure.
Fig. 34 is a cross-sectional view illustrating an example of an interface of
the electrical
switching device and case of Fig. 33.
Fig. 35 is an exploded cutaway view of the embodiment of Fig. 33.
Fig. 36 is a cross-sectional view illustrating an example of an interface of a
wall of the
case and a wall of the electrical switching device.
Fig. 37 is a cutaway view illustrating a bulkhead according to some inventive
principles
of this patent disclosure.
Fig. 38 is an exploded cutaway view of the embodiment of Fig. 37 from a
different angle.
Fig. 39 is a cutaway view illustrating a circuit board in the assembly of Fig.
38 according
to some inventive principles of this patent disclosure.
Fig. 40 is a cutaway view illustrating a circuit board according to some
inventive
principles of this patent disclosure.
Fig. 41 is the cutaway view of Fig. 39 without the circuit board.
Fig. 42 is a cutaway view illustrating a bulkhead and terminals according to
some
inventive principles of this patent disclosure.
Fig. 43 is the cutaway view of Fig. 42 rotated to illustrate a vent according
to some
inventive principles of this patent disclosure.
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Fig. 44 is a cross-sectional view illustrating a second chamber according to
some
inventive principles of this patent disclosure.
Fig. 45 is a cross-sectional view illustrating a wall of the second chamber of
Fig. 44
according to some inventive principles of this patent disclosure.
Fig. 46 is a block diagram illustrating an example of guiding a blast
according to some
inventive principles of this patent disclosure.
Fig. 47 is a block diagram illustrating various zones according to some
inventive
principles of this patent disclosure.
Fig. 48 is a block diagram illustrating additional zones of the circuit board
of Fig. 47
according to some inventive principles of this patent disclosure.
Fig. 49 is a perspective view illustrating an electrical switching component
according to
some inventive principles of this patent disclosure.
Fig. 50 is a cutaway view illustrating an actuator according to some inventive
principles
of this patent disclosure.
Fig. 51 is a perspective view illustrating a case according to some inventive
principles of
this patent disclosure.
Fig. 52 is a side view illustrating the protrusion and mounting ear of Fig.
51.
Fig. 53 is a plan view of an example of a mounting site for the assembly of
Fig. 51.
Fig. 54 illustrates an embodiment of an electrical switching module according
to some
inventive principles of this patent disclosure.
DETAILED DESCRIPTION
Fig. 1 illustrates an embodiment of an electrical switching module according
to some
inventive principles of this patent disclosure. In this embodiment, the module
1 includes a case
10. The case 10 substantially encapsulates an electrical switching device 12
and a controller 14.
The electrical switching device 12 can be a relay, a circuit breaker, a
switch, or any other type of
device or combination of devices that can control current to a load 18. The
electrical switching
device 12 can be an air-gap relay, a solid-state relay, a combination of such
relays, or the like. In
particular, in an embodiment, the electrical switching device 12 can be
configured to be coupled
to line wiring' 20. Load wiring 21 can couple the electrical switching device
12 to the load 18.
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The controller 14 can include a processor or processors such as digital signal
processors,
programmable or non-programmable logic devices, microcontrollers, application
specific
integrated circuits, state machines, or the like. The controller 14 can also
include additional
circuitry such as memories, input/output buffers, transceivers, analog-to-
digital converters,
digital-to-analog converters, or the like. In yet another embodiment, the
controller 14 can
include any combination of such circuitry. Any such circuitry and/or logic can
be used to
implement the controller 14 in analog and/or digital hardware, software,
firmware, etc., or any
combination thereof.
The controller 14 is coupled to the electrical switching device 12.
Accordingly, the
controller 14 can be configured to monitor the electrical switching device 12.
For example, the
controller 14 can be configured to sense aspects associated with the
electrical switching device
12 such as current, voltage, amplitude, frequency, or the like. The controller
14 can be
configured to actuate the electrical switching device 12. As the electrical
switching device 12
and the controller 14 are substantially encapsulated by the case 10, higher
level functionality can
be presented to a user of the module 1.
In an embodiment, the module 1 can also include a communication interface 16.
The
communication interface 16 can include any variety of interfaces. For example
the
communication interface 16 can include a wired or wireless interface. The
communication
interface 16 can include a serial interface or a parallel interface. In an
embodiment, a MODBUS
interface can be used. In another embodiment, an Ethernet interface,
controller area network
interface, or the like can be used.
Accordingly, the controller 14 can be configured to communicate monitored
parameters,
expose functionality of the electrical switching device 12, provide
functionality beyond actuation
for the electrical switching device 12, or the like to a user. Thus, the
module 1 can present more
functionality beyond switching control.
Moreover, although a communication network such as a controller area network,
a
MODBUS network, or the like can be used, a more general purpose network can be
used. For
example, as described above the communication interface 16 can include an
Ethernet interface.
Each module could have a globally unique address, such as an IPv6 address.
Thus, each module
could be individually accessible, controllable, monitorable, or the like from
an arbitrary location
or system.
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Fig. 2 illustrates an embodiment of an electrical switching module with a
position sensor
according to some inventive principles of this patent disclosure. In this
embodiment, the
electrical switching device 12 includes an actuator 30. The actuator 30 can
include a mechanism
coupled to a contact of the electrical switching device 12.
In an embodiment, the actuator 30 can be amanual actuator. The manual actuator
can be
operable by a user to actuate the electrical switching device 12. For example,
the manual
actuator can be accessible through the case 10, coupled to a structure
accessible through the case
and coupled to the electrical switching device 12, or the like. For example, a
lever of the
electrical switching device 12 can be moved to actuate the electrical
switching device 12. The
10 lever of the electrical switching device 12 can be coupled to another lever
that is operable
through the case 10. However, in other embodiments, other manual controls such
as buttons,
knobs, switches, or the like can be used.
The module 2 can include a position sensor 32. The position sensor is
configured to
sense a state of the electrical switching device 12. A state of the electrical
switching device 12
can include open, closed, fault, transitioning, or the like. For example, the
position sensor 32 can
be coupled to a manual actuator. The position sensor 32 can be configured to
sense a position of
the manual actuator. In another embodiment, the position sensor 32 can be
coupled to the
electrical switching device 12 regardless of the presence of a manual actuator
to sense the state.
The position sensor 32 can include a variety of sensors. For example, a
photointerruptor
can be used as a position sensor 32. A manual actuator can be coupled to the
photointerruptor
such that an actuation of the manual actuator can actuate the photointerruptor
in response to the
state of the electrical switching device 12.
In another example, a mechanical contact sensor that makes or breaks an
electrical
circuit can be used. In yet another example, a digital position encoder can be
used to sense the
position of a structure of the electrical switching device 12. Any sensor that
can sense position,
movement, acceleration, or the like can be used. That is, the position sensor
32 can be
configured to sense more than position, unable to sense actual position but
infer position from
velocity, or the like. The electrical switching device 12 can be coupled to
any of these position
sensors 32 such'that the state of the electrical switching device 12 can be
sensed.
Fig. 3 illustrates an embodiment of an electrical switching module with a zero-
crossing
detector according to some inventive principles of this patent disclosure. In
this embodiment,
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the module 3 includes a zero-crossing detector 40. The zero-crossing detector
40 is configured
to detect a zero-crossing associated with the electrical switching device 12.
For example, with an alternating current (AC) line voltage on the line wiring
20, the
instantaneous voltage across the electrical switching device 12 can vary
around zero volts. As
illustrated the zero-crossing detector 40 is coupled to the line wiring 20.
Accordingly, the zero-
crossing detector 40 can be configured to detect a zero-crossing of the
voltage on the line wiring.
In another embodiment, the zero-crossing can be a current zero-crossing. The
zero-
crossing detector 40 can be configured to sense such a current zero-crossing.
Accordingly, the
zero-crossing detector 40 can be configured to detect a variety of zero-
crossings. Moreover, the
zero-crossing detector 40 can be configured to detect multiple zero-crossings.
For example,
depending on the load 18, the zero-crossing of the current. can, be out of
phase with the voltage
zero-crossing. The zero-crossing detector 40 can be configured to sense both
voltage and current
zero-crossings. Furthermore, although the zero-crossing detector 40 is
illustrated coupled to the
line wiring 20 coupled to the electrical switching device 12, the zero-
crossing detector 40 can be
coupled to any appropriate circuitry to sense the corresponding zero-
crossings.
The zero-crossing detector 40 can be coupled to the controller 14.
Accordingly, the
controller 14 can be configured report the zero-crossings, operate in response
to the zero-
crossings, or the like. For example, as will be described in further detail
below, the controller 14
can be configured to actuate the electrical switching device 12 in response to
the zero-crossing
detector 40.
Fig. 4 illustrates an embodiment of an electrical switching module with a
current sensor
according to some inventive principles of this patent disclosure., In this
embodiment, the module
4 includes a current sensor 50. The current sensor 50 is configured to sense a
current passing
through the electrical switching device 12. Moreover, the current sensor 50
can be configured to
25, sense other currents associated with the electrical switching device 12.
For example, a current
used in energizing a coil of the electrical switching device 12 can be
measured.
The current sensor 50 can be a variety of devices. For example, the current
sensor can be
a hall-effect sensor, an inline current sensor, or the like. The current
sensor 50 can be coupled to
the controller 14. Accordingly, the controller 14 can be configured to report
the sensed current,
operate in response to the sensed current, or the like.
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Fig. 5 illustrates an embodiment of an electrical switching module with a
voltage sensor
according to some inventive principles of this patent disclosure. In this
embodiment, the module
includes a voltage sensor 60. The voltage sensor 60 is coupled to the
electrical switching
device 12. The voltage sensor 60 can be configured to sense a voltage
associated with the
5 electrical switching device 12. For example, as illustrated, the voltage
sensor 60 can be
configured to sense a voltage on line wiring 20 coupled to the electrical
switching device 12.
Alternatively, the voltage sensor can be configured to sense a voltage on the
load wiring 21, a
power supply for driving the, actuation of the electrical switching device 12,
or the like. The
voltage sensor 60 can be configured to sense any voltage associated with the
electrical switching
device 12.
The voltage sensor 60 can include any variety of voltage sensors. For example,
the
voltage sensor 60 can be single ended or differential. The voltage sensor 60
can sense direct
current (DC) or alternating current (AC) voltages. The voltage sensor 60 can
have a single input
or multiple inputs.
In another embodiment the voltage sensor 60 can include conditioning circuitry
to
transform the monitored voltage into a voltage. suitable for digitizing by the
controller 14. For,
example, the voltage sensor 60 can include rectification and scaling to
transform a 120 VAC
voltage into a 2.5 VDC voltage, or the like. Accordingly, an analog to digital
converter of the
controller 14 can sense the 2.5 VDC voltage.
In an embodiment, the sensing of various voltages, currents, and the like
within the case
10 of the module can allow power measurement at a module level resolution. For
example,
multiple modules can be installed within a load center, electrical cabinet, or
the like. Each
module can monitor the current and voltage associated with the electrical
switching device 12.
Accordingly, the power delivered to each load 18 can be monitored. The
controller 14 can be
configured to monitor such measurements, record such measurements, report the
measurements
to a system master or user, or the like.
Fig. 6 illustrates an embodiment of an electrical switching module with a
communication
interface according to some inventive principles of this patent disclosure. In
this embodiment,
the communication interface 16 is coupled to a terminal 70. The communication
interface 16 is
also coupled to communication terminals 72. The communication terminals
include terminals
over which communication signals are transmitted.
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In this embodiment, the terminal 70 is separate from the communication
terminals 72.
When installed in a mounting site, a voltage can appear on the terminal 70.
The voltage can
correspond to a parameter of the communication interface. For example, the
voltage can be
interpreted into data associated with the communication interface.
In an embodiment, each mounting site for a module 6 within a cabinet, panel,
or other
enclosure can have a different voltage appear at a connection for the
associated terminal 70. The
controller 14 can be configured to determine an address for the module 6 in
response to the
voltage. Thus, each module 6 can have a unique address resulting from a unique
voltage. As a
result, substantially identical modules 6 can be installed in substantially
identical mounting sites
within an enclosure yet each module can be addressed individually.
Although a voltage has been described as being present on the terminal,
another aspect of
the terminal can be used. For example, a current, an AC amplitude, a digital
signal, or the like
can be sensed.
Although a single terminal 70 has been described multiple terminals 70 can be
used. For
example, a cabinet can be divided into multiple regions with each region
including mounting
sites for multiple modules. A first terminal 70 can be used as described above
to determine a
first voltage. A second terminal 70 can be used to determine a second voltage.
The combination
of the two voltages can be used to select a unique address. In another
example, the states of
eight terminals 70 can form an eight bit value for use in determining an
address. Any number of
20. terminals 70 can be used to detect any number of signals to define the
parameters of the
communication interface 16.
Although an address has been used as an example of a parameter for a
communication
interface 16, a parameter can include other aspects of the communication
interface 16. For
example, a parameter can include a type of communication network, a
master/slave indication, or
the like.
Although the communication interface 16 has been illustrated in each of Figs.
1-6, a
module need not have a communication interface 16, yet can still have the
various other circuitry
and functionality described above. For example, the various circuitry
described above can be
used in monitoring an electrical switching device for a fault. Such a fault,
the underlying
information generating the fault, or the like can, but need not, be
communicated through a
communication interface. Rather, such a fault can be communicated to a user
through a different
CA 02709513 2010-07-14
user interface. For example, the state of a manual actuator can be changed to
indicate the fault.
In another example, another user interface within the module, such as a light
emitting diode
(LED) can be illuminated to indicate the fault, the type of fault, or the
like. Moreover, a fault
need not be the only state communicated through such a user interface.
Accordingly, the module can act as a stand alone module without any external
processing
monitoring, or the like. Information about the module, the electrical
switching device 12, or the
like can be provided to a user beyond mere on, off, and tripped states, or the
like.
Fig. 7 illustrates an embodiment of an electrical switching module with a
dimming
interface according to some inventive principles of this patent disclosure. In
this embodiment,
the module 7 includes a dimming interface 74. The dimming interface 74 can be
any variety of
dimming interfaces. For example, the dimming interface 74 can be a digital
addressable lighting
interface (DALI), a 0-1OV load interface, a digital signal interface (DSI), or
any other interface
for dimming control.
In addition, in an embodiment, the dimming interface can be disposed in a
region of the
module 7 along with the electrical switching device 12. For example, the
electrical switching
device 12 can be wired as a class 1 device. The dimming interface 74 can also
be wired as a
class 1 device even though it has an interface to the controller 14. That is,
even though the
controller 14 is disposed in a region of the module, such as a class 3 region,
the connection to the
dimming interface 74 across the boundary 76 can be formed such that the
electrical regions are
appropriately isolated.
Although a variety of individual elements of a module have been described
above, a
given module can include any combination of such elements. Moreover, any
variety of different
modules can be used in concert as the communication interface 16 can be
configured to allow the
controller 14 to be interrogated for its capabilities.
Fig. 8 illustrates an analog signal measurement circuit capable of signal
transmission
across a voltage boundary according to some inventive principles of this
patent disclosure. As
described above, a variety of voltages, currents, signals, or the like can be
monitored. Such
parameters can be transformed into an analog signal suitable for
communication. For example,
an amplitude of a 120VAC signal can be converted into a 2.5 VDC signal. The
analog source 80
represents such circuitry, coupling, or the like to obtain such a signal.
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Once obtained, the analog signal can be used to modulate a pulse width. Pulse
width
modulated (PWM) signal generator 82 can be configured to generate a PWM signal
having a
pulse width corresponding to the analog signal. For example, the pulse width
can correspond to
a voltage measured by a voltage sensor 60, current sensor 50, described above,
or the like.
An isolator 84 can span a boundary 86 between a first voltage region and a
second
voltage region. For example, a class 1 region and a class 3 region can be
separated by the
boundary 86. The isolator can allow a signal to cross the boundary, yet
maintain the isolation.
The isolator 84 can be any variety of isolator. For example, an optoisolator,
a transformer, or the
like can be used as an isolator 84.
The PWM signal can be propagated across the boundary 86 through the isolator.
In
particular, as the information contained within the PWM signal is the pulse
width, a variation in
amplitude of the PWM signal has a reduced if not negligible effect on a
quality of the transmitted
signal. However, any aging, degradation, or the like of the isolator 80 can
have a reduced effect
on the recovered analog signal.
In this embodiment, a controller 88 and a filter 89 are both illustrated as
receiving the
PWM signal. Thus, the filter 89 can be configured to filter the PWM signal to
another analog
signal. In an embodiment, the recovered analog signal can, but need not, be
substantially
identical to the original analog signal. That is, the recovered analog signal
can be scaled
differently, include an offset, or the like.
In addition, the controller 88 can receive the PWM signal. As will be
described in further
detail below, additional information beyond the analog signal can be
communicated through the
PWM signal. However, the controller 88 can also be configured to recover the
analog signal
from the PWM signal. For example, the controller can be configured to measure
a pulse width
of the PWM signal. Thus, the encoded analog signal can be recovered.
Fig. 9 illustrates the circuit of Fig. 8 with a zero-crossing detector
according to some
inventive principles of this patent disclosure. In this embodiment, the PWM
signal generator 94
is coupled to a zero-crossing detector 92. The zero-crossing detector 92 is
configured to detect a
zero-crossing associated with an electrical switching device 90.
The PWM signal generator 94 is configured to generate a PWM signal having a
pulse
width corresponding to the analog signal. However, the PWM signal generator 94
is also
configured to generate a PWM signal 'in response to the zero-crossing detector
92. For example
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the PWM signal can be substantially synchronized with zero-crossings detected
by the zero
crossing detector 92. Thus, the PWM signal that is propagated through the
isolator 84 has two
distinct sets of information encoded within. That is, the analog signal and
the zero-crossings are
encoded in a single PWM signal.
In particular, in an embodiment the time of the zero-crossing can be
represented by an
edge of the PWM signal. For example, each rising edge can be substantially
coincident with a
zero-crossing However, in an embodiment, the detected zero-crossing can be
offset in time,
phase, or the like from the actual zero-crossing. Accordingly, the PWM signal
can be adjusted,
the processed PWM signal can be adjusted, or the like to identify the actual
zero-crossing.
As described above, the controller 88 can be configured to sense the analog
signal within
the PWM signal. In addition, the controller 88 can be configured to sense a
zero-crossing from
the PWM signal. For example, the controller 88 can include an edge triggered
interrupt
responsive to rising edges. Thus, the controller 88 can receive an interrupt
for each zero-
crossing.
Fig. 10 illustrates a pulse width modulated pulse train synchronized with a
zero-crossing
according to some inventive principles of this patent disclosure. The pulse
train 100 has a series
of pulses having a width 102. The pulses occur with a period 104. As described
above, the pulse
width can encode an analog signal. Pulse width 106, illustrated in phantom,
illustrates a different
pulse width corresponding to a different level of the analog signal.
As illustrated the pulse with width 102 and the pulse with width 106 share a
common
rising edge. Thus, regardless of the pulse width, assuming it is not
substantially 0% or 100% of
the period 104, a rising edge can occur substantially coincident with the zero-
crossing. That is,
the period 104 can convey a separate piece of information, such as the zero-
crossing described
above.
In an embodiment, multiple zero-crossings can be communicated through multiple
PWM
signals. Although a single zero-crossing detector 92 has been described above,
the zero-
crossings detected by the zero-crossing detector 92 can, but need not, be the
only zero-crossings,
detected. For example, a zero-crossing of a current through electrical
switching device 12 may
be out of phase with a zero-crossing of a voltage coupled to the electrical
switching device 12.
Accordingly, a first PWM signal can be substantially synchronized with a first
zero-
crossing signal. A second PWM signal can be substantially synchronized with a
second zero-
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crossing signal. Thus, any number of different zero-crossing signals can be
communicated
across a voltage region boundary as desired.
Although the PWM signal has been described as substantially synchronized with
zero-
crossings, such synchronization can, but need not, include substantially
similar frequencies. For
example, a voltage zero-crossing can occur in a 60 Hz signal at 120 Hz.
However, the PWM
signal can be synchronized to 60 Hz, 30 Hz, or the like. Similarly, the PWM
signal can be
synchronized to a higher frequency, such as 240 Hz, 480 Hz, or the like.
However, in such
circumstances, an additional signal may be used to determine which edges of
the PWM signal
are substantially coincident with a zero-crossing.
Fig. 11 illustrates an embodiment of a combined signal measurement circuit and
zero
crossing detector according to some inventive principles of this patent
disclosure. In this
embodiment, the circuit includes an isolator 108 spanning the boundary 86. The
isolator 108 has
an actuator 109. The actuator 109 is illustrated as an LED; however, other
actuators can be used
according to the type'of the isolator 108.
The actuator 109 is coupled in series with a charge storage circuit 113 and a
current
source 111. In an embodiment, at least one of the charge storage circuit 113
and the current
source is responsive to the line voltage 115. For example, the current source
111 can be
configured to source or sink a current during substantially only one half-
cycle of the line voltage
115. In another example, the charge storage circuit 113 can be configured to
charge during
substantially only one half-cycle of the line voltage 115.
In yet another example, both the current source and charge storage circuit can
be
configured to operate during such half-cycles, but on opposite half cycles.
Using this example,
on a positive half-cycle, the charge storage circuit 113 can be configured to
charge to a voltage
corresponding to the line voltage 115. The current source 111 can be
configured to not sink
current during the positive half-cycle. Asa result, the charge in the charge
storage circuit 113
can remain substantially charged.
In the negative half-cycle, the charge storage circuit 113 can be configured
to not charge.
The current source 111 can be configured to sink a current. Thus, the charge
storage circuit 113
can be discharged through the actuator 109, actuating the isolator 108. Since
the charge in the
charge storage device 113 corresponds to the line voltage 115, the discharge
time can correspond
to the line voltage 115. Thus, the time that the isolator 108 is actuated
corresponds to the line
14
CA 02709513 2010-07-14
voltage 115. In addition, since the discharge of the charge storage circuit
113 can begin on a
transition from the positive half-cycle to the negative half-cycle, the
beginning of the actuation
of the isolator 108 corresponds to the zero-crossing of the line voltage 115.
Although the line voltage 115 has been used as an example of a signal that can
be used
.5 with the circuit, a line current, or other periodic signal could similarly
be used. Furthermore,
although a particular description of sourcing or sinking current has been
used, current can be
controlled in the appropriate direction. Moreover, the orientation of the
various components can
change based on the polarity of voltages, currents, components or the like.
Fig. 12 illustrates another embodiment of a combined signal measurement
circuit and
zero crossing detector according to some inventive principles of this patent
disclosure. In this
embodiment, when the line voltage 115 is in a positive half-cycle, a voltage
divider is created
with resistors RIO, Rl 1, and diode Dl1. This voltage can charge capacitor CIO
through diode
D10.
When diode Dl 1 is conducting, node N 10 will be substantially at one diode
voltage drop.
Accordingly, the base-emitter junction of transistor Q10 will be reverse
biased, turning off
transistor Q10. As a result, no current will flow through the LED D16 of the
isolator 119,
allowing capacitor C 10 to charge.
When the line voltage 115 transitions to the negative half-cycle, node N 10
will be pulled
down two diode voltage drops below the. neutral 121. As a result, transistor
Q10 will turn on,
allowing diodes D14 and D15 to conduct and turn on transistor Q11. A
substantially constant
current can then flow through LED D16. Since diode Dl0 is now reverse biased,
capacitor C10
can stop charging through diode D 10. LED D16 can remain on until the charge
on the capacitor
C10 is discharged substantially. Thus, the LED D16 will remain on a time
according to the line
voltage 115 and will turn on substantially at the transition from the positive
half-cycle to the
negative half-cycle.
Fig. 13 illustrates a circuit spanning a voltage region boundary according to
some
inventive principles of this patent disclosure. In this embodiment, the
isolator is an optoisolator
110 with a light emitting diode (LED) and a phototransistor. The LED is
coupled between a
power supply 112 and a PWM signal generator 82. In an embodiment, the power
supply 112 is
coupled to a line voltage 117. Accordingly, the LED can be switched on and off
according to a
PWM signal.
CA 02709513 2010-07-14
The phototransistor is coupled to a resistor R and a ground 114. The resistor
R is coupled
to a power supply 116. As the phototransistor is alternately turned on an off
by the actuated
LED, the node 118 is alternately pulled up by the resistor R and pulled down
by the
phototransistor. Thus, the PWM signal can be propagated across the boundary
86. Although in
this embodiment, the PWM signal that is propagated corresponds to the
generated PWM signal,
the components, connections, or the like can be selected such that the PWM
signal on node 118
can be inverted when crossing the boundary 86.
In an embodiment, the power supply 112 can receive a line voltage from a line
terminal
114. The power supply 112 can be configured to generate a power voltage for
the LED of the
optoisolator. The LED of the optoisolator 110 can have a threshold voltage
below which the
LED will not substantially actuate the optoisolator 110. The power supply 112
can be
configured such that at a minimum specified voltage of the line voltage, the
power voltage is
substantially equal to the threshold voltage of the LED. That is, if the line
voltage is below the
minimum specified voltage, the power voltage will be below the threshold
voltage of the photo
diode. As a result, a relatively smaller amount of current will be drawn from
the power supply
112 than in operation. Thus, the current consumed by the circuit can be
reduced until the
minimum specified voltage has been met or exceeded.
Fig. 14 illustrates a zero-crossing synchronization circuit according to some
inventive
principles of this patent disclosure. In this embodiment, the controller 14 is
coupled to a memory
100. The memory is configured to store a calibration time 102. The memory 100
can be any
variety of memory. For example, the memory can be non-volatile or volatile
memory, static or
dynamic memory, or the like. Moreover, the memory 100 can be internal to the
controller 14,
external, or a combination.
As described above, the controller 14 can be coupled to a zero-crossing
detector 40 and
receive a zero-crossing. The controller 14 can be configured to actuate the
electrical switching
device in response to the zero-crossing detector and a calibration time. The
calibration time 102
can be a variety of different times. For example, the calibration time 102 can
be an actuation
time, an offset from an actuation time, a delay between a zero-crossing and an
energization time,
or the like.
Fig. 15 illustrates an example of a timing of an actuation of the electrical
switching
device relative to zero-crossings of a waveform according to some inventive
principles of this
16
CA 02709513 2010-07-14
patent disclosure. In this embodiment, reference line 112 represents the zero
level associated
with waveform 110. The waveform 110 can represent the parameter having the
zero-crossing,
such as a voltage or current.
In this embodiment, time 120 is an actuation time 120. For example, the stored
calibration time 102 can be the actuation time 120. The delay time 124 was
calculated such that
a total of the actuation time 120 and the delay time 124 was substantially
equal to an integer
multiple of the zero-crossing period. In this embodiment, the total time
period 122 is
substantially equal to three zero-crossing periods.
The controller 14 is configured to receive a zero-crossing, such as zero-
crossing 114.
The controller 14 does not actuate the electrical switching device 12 until a
delay time 124 after
the zero-crossing 114. In particular the electrical switching device 12 is
actuated at time 116.
The electrical switching device 12 takes time 120 to actuate such that the
actuation is not
substantially complete until time 118. Since the total time 122 including the
delay time 124 and
the actuation time 120 was an integer multiple of the zero-crossing period and
the total time 122
began substantially at a zero-crossing at time 114, the completion of the
actuation will occur
substantially at the zero-crossing at time 118, three zero-crossing time
periods from the zero-
crossing at time 114. Thus, the actuation of the electrical switching device 1
can be substantially
synchronized with a zero-crossing.
Although a single zero-crossing sequence has been described as being used to
actuate the
electrical switching device 12, different zero-crossing sequences can be used
for different
operations of the electrical switching device 12. For example, a zero-crossing
sequence for the
voltage of the line wiring 20 can be used when actuating the electrical
switching device 12 to
close the contacts of the electrical switching device 12. Thus, as the
contacts are closed, the
voltage drop across the contacts can approach a minimum. When the contacts of
the electrical
switching device 12 are to be opened, the opening can be substantially
synchronized with the
zero-crossings of the current flowing through the electrical switching device
12.
Fig. 16 illustrates another zero-crossing synchronization circuit according to
some
inventive principles of this patent disclosure. In this embodiment, the
controller 14 is configured
to measure a delay time between an energization of the electrical switching
device and an
actuation of the electrical switching device.
17
CA 02709513 2010-07-14
In this embodiment, a position sensor 32 is configured to sense a state of the
electrical
switching device 12. For example, as described above, the position sensor 32
can sense a
position of the actuator 30. As a result, the state of the electrical
switching device 12 can be
sensed. However, in another embodiment, other techniques can be used to sense
the state of the
electrical switching device 12. For example, an instantaneous voltage across
the electrical
switching device 12, a current passing through the electrical switching
device, or the like can be
used to sense the state.
The controller 14 can be configured to measure a delay time between an
energization of
the electrical switching device 12 and a change in the state sensed by the
position sensor 32. As
a result, the actuation time can be determined. The actuation time can be used
to update the
calibration time 102. Thus, a different delay time 124, different actuation
time 120, or the like
can be stored as the calibration time 102.
Fig. 17 illustrates an example of a measurement of an actuation time of the
electrical
switching device relative to zero-crossings of a waveform according to some
inventive principles
of this patent disclosure. Delay time 124 and actuation time 120 are
illustrated for reference.
However, in this embodiment, the actuation time of the electrical switching
device 12 has
changed to 134. That is, the electrical switching device 12 is energized at
time 116 after the
delay time 124. The electrical switching device 12 is actuated by the
actuation time 134 at time
130, after the zero-crossing at time 132. Thus, because the actual actuation
time 134 is different,
the actuation does not occur on the desired zero-crossing at time 132.
However, as described above, the actuation time of the electrical switching
device 12 can
be measured. That is, by detecting the time between the energization at time
116 and the actual
actuation at time 130, a new actuation time 134 can be determined.
Accordingly, the delay time
124 can be adjusted such that a total of the new delay time 139 and the
recently measured
actuation time 134 can be substantially equal to an integer multiple of a zero-
crossing period.
That is, the new delay time 139 can be updated, the actuation time 136 can be
updated, or the
like.
In an embodiment, the actuation time can be measured whenever the electrical
switching
device 12 is actuated. Accordingly, the time delay 139 can be calculated in
response to recent
measurements. Moreover, as the electrical switching device 12 is actuated,
multiple
measurements of the actuation time 136 can be obtained. Using the multiple
measurements, a
18
CA 02709513 2010-07-14
variation of the actuation time can be determined. As with any measurement
technique, some
variation may be present. However, variation greater than or equal to a
threshold can be
identified within the multiple measurements.
For example, the variation can be an erratic variation with substantially
unpredictable
actuation times. If the magnitude of the variation crosses the threshold, the
variation can be
reported by the controller 14, a fault can be indicated, the controller 14 can
open the electrical
switching device 12, or the like. In other words, the measured actuation time
136 can be used for
any purpose beyond adjustment of the calibration time for the. module.
In another example, the actuation time can be increasing monotonically. Such a
change
can be an indication of aging, but may not indicate that the electrical
switching device 12 is
failing, operating in an unsafe manner, or the like. The controller 14 can be
configured to
analyze the various actuation times to make such a determination.
In an embodiment, the difference between a new actuation time, such as time
134, and an
earlier actuation time, such as time 120, can be greater than the earlier
delay time 124. That is,
the new time 134 can exceed the integer multiple of zero-crossings of the
total of the delay time
124 and the earlier actuation time 120. Accordingly, the new delay time 139
can be selected for
a different integer multiple of zero-crossing periods. That is, a greater
number of zero-crossing
periods can be included in the total time. Similarly, if the measured
actuation time 136 is
sufficiently less, a reduced number of zero-crossing periods can be included
in the total.
Moreover, in an embodiment, the number of zero-crossing periods used as th e
total of the
delay time 139 and the actuation time 136 need not be the minimum number. For
example, as
illustrated, three zero-crossing periods are included in the total of the
delay time 139 and the
actuation time 136. However, the delay time 139 could be set such that four or
more zero-
crossing periods can be included. That is, the delay time 139 can be, but need
not be a fraction
of a single zero-crossing period.
As described above, a single zero-crossing has been described with respect to
the timing
and measurement of energization and actuation. However, different calibration
times, zero-
crossings, delay times, or the like can be used according to the associated
actuation. For
example, an actuation of the electrical switching device 12 to close the
contacts can use the
voltage zero-crossings with an associated voltage zero-crossing calibration
time. An actuation of
the electrical switching device 12 to open the contacts can use the current
zero-crossings with an
19
CA 02709513 2010-07-14
associated current zero-crossing calibration time, both of which may be
different from the
corresponding voltage related parameters.
Fig. 18 illustrates a zero-crossing detector according to some inventive
principles of this
patent disclosure. In this embodiment, a clamp 142 is configured to clamp an
alternating current
(AC) signal. For example, the AC signal can be the line voltage 140 on line
wiring. However,
in other embodiments, the AC signal can be different, for example, the current
flowing through
the electrical switching device 12, or the like.
A pulse generator 144 is coupled to the clamp 142 and configured to generate a
pulse in
response to an edge of the clamped AC signal. An isolator 146 is coupled to
the pulse generator
144 and configured to be actuated by the pulse. Accordingly, the pulse from
the pulse generator
can be propagated across the voltage boundary 148 to generate a pulse on line
150.
In particular, as the AC signal is clamped, the clamped AC signal can
transition during
low voltage portions of the AC signal. For example, as the AC signal crosses
through
approximately zero volts, the clamped AC signal can also transition. Thus, the
transitions, or
edges of the clamped AC signal correspond to the zero-crossings.
In an embodiment, the information conveyed in the pulses is conveyed in the
edge.
Accordingly, a minimum pulse width sufficient to be detected can be used. For
example, a pulse
width of about 100 s can be used. As a result, the isolator 146 can be
configured to be actuated
for only about 100 is. Thus, with a 120 Hz zero-crossing frequency,
corresponding to a period
of about 8.3 ms, a 100 is pulse width is a duty cycle of about 1.2%.
Accordingly, for a majority
of the time of a zero-crossing period, the isolator 146 can be disabled. In
particular, with an
optoisolator described above, the LED can be disabled for the majority of the
zero-crossing
period.
As a result, a power consumption of the circuit can be reduced. For example,
if the
clamped AC signal is used to turn the LED on and off, a duty cycle of about
50% is achieved.
Thus, the LED is'on for about 50% of the time. In contrast, if a 1.2% duty
cycle as described
above, the LED is turned on only about 1.2% of the time, yet the same zero-
crossing information
is conveyed. That is, the zero-crossing information can be obtained with a
reduced amount of
power.
In particular, the reduction in power can occur with respect to a power supply
generated
from the line voltage. For example, the power supply for the LED actuation can
be generated
CA 02709513 2010-07-14
from a line voltage. An amount of current that is allowed to be sunk to a
neutral terminal can be
limited. Accordingly, power consumption can be reduced, leaving more power for
other devices,
or the like.
Fig. 19 illustrates an example of the pulse generator of Fig. 18 according to
some
inventive principles of this patent disclosure. In this embodiment, a charge
storage device 160 is
configured to store a charge. The charge storage device 160 can include a
capacitor, inductor, or
the like. The charge storage device 160 can also include various other
components, such as
resistors, current limiters, or the like such that the charge and discharge
time can be set as
desired.
The charge storage device 160 is coupled to diodes D 1 and D2. The diodes D 1
and D2
are coupled to the charge storage device 160 in opposite directions. Thus,
current flowing
towards and away from the charge storage device 160 can take substantially
different paths as
illustrated by paths 161 and 163.
The diodes D1 and D2 are coupled to the actuating element 162 of the isolator
146. For
example, the actuating element 162 can be the LED of the optoisolator
described above. In
particular, the diodes D 1 and D2 can be coupled to the actuating element 162
such that the
current paths 161 and 163 each flow the same direction through the actuating
element 162. That
is, even though the paths 161 and 163 are substantially different, the paths
161 and 163 share the
same path through the actuating element 162.
Controllable current sources 166 and 168 are responsive to the control 164.
The control
164 represents the driving circuitry that sources or sinks the current of the
paths 161 and 162. It
particular, the current sources 166 and 168 are not ideal sources. That is the
current that is
sourced or sunk can fall as the charge storage device 160 is charged or
discharged.
The control 164 is configured to drive the current sources in response to the
clamped AC
signal from the claim 142. That is, as described above, the clamped AC signal
can be a square
wave signal with about a 50% duty cycle. The current sources 166 and 168 can
be configured to
be alternately activated in response to the different states of the clamped AC
signal. Thus, the
charge storage device 160 can be charged and discharged in response to the
states of the clamped
AC signal.
As described above, the current sources 166 and 168 are non-ideal sources. In
particular,
the current sources 166 and 168 are each configured to charge or discharge the
charge storage
21
CA 02709513 2010-07-14
device 160 to a corresponding rate. As the charge rate defines the time that
the charge storage
device 160 takes to charge or discharge, and effectively disable the
corresponding current source
166 to 168, the time that the actuating element 162 is actuated can be
controlled. As described
above, regardless of the direction of charging or discharging of the charge
storage device 160,
the current passes through the actuating element 162 in the same direction.
Thus, the actuating
element 162 will be actuated substantially during the charging or discharging
operation.
However, the current can drop below a threshold to activate the actuation
element 162 during a
steady state condition. Thus, a pulse can be generated with a finite width.
Moreover, as the control of the current source 166 and 168 changes as the
clamped AC
signal changes, a new charge or discharge cycle will begin on each change of
state. As described
above, with the clamped AC signal, the transitions can correspond to a zero-
crossing. Thus, a
new charge or discharge cycle will begin on the zero-crossing, and hence, the
actuating element
162 will be actuated on the zero-crossing. The time the actuating element 162
is actuated will be
dependent on the charge or discharge time of the charge storage device 160.
Fig. 20 illustrates another example of the pulse generator of Fig. 18
according to some
inventive principles of this patent disclosure. In this embodiment, the charge
storage device 160
is a capacitor C 1. The capacitor Cl is coupled between the diodes and the
power supply 180.
Although a single power supply 180 connection is illustrated, the capacitor Cl
can represent
capacitance to more than one reference voltage.
A first terminal of the actuating element 160 is coupled to a transistor Ti.
Transistor T1
is coupled to power supply 180 and configured to receive a control output from
the drive circuit
182 at a common node 190. The drive circuit 182 includes any circuitry to
condition the
clamped AC signal 192 appropriately to drive the common node 190.
.A second terminal of the actuating element 162 is coupled to a diode D3.
Diode D3 is
also coupled to the common node 190. In this embodiment, when the control
output at the
control node 190 is a low signal, current is conducted along path 186,
charging the capacitor 180
and pulling down node 194. During this time, the actuating element 162 is
actuated in response
to the current. Eventually, node 194 will be pulled down sufficiently such
that the voltage drop
across the various components along the path 186 and, in particular, the
actuating element 162,
will be insufficient to actuate the isolator 146. Thus, the actuating element
162 will be actuated
substantially only for such a time period.
22
CA 02709513 2010-07-14
When the control node 190 is driven with a high signal, transistor Ti
conducts. Diode
D3 is substantially reversed biased and does not conduct. Thus, current flows
along path 188,
pulling up node 194, reducing the charge on the capacitor Cl. Similarly, the
transistor Ti will
pull up node 194 until the voltage drop is insufficient. Again, the actuating
element 162 is
actuated for the time node 194 is pulled up.
Although in this embodiment, a transistor Ti and diode D3 have been described,
other
circuitry can be used to drive the terminals of the actuating element 162. For
example, transistor
Ti could be replaced with a diode and the drive circuit 182 can be configured
to supply the
current for path 188. Moreover, although the terms pull up and pull down have
been used above,
the circuitry, charge storage element 160, or the like can be configured where
the flow of
current, control, or the like is reversed.
Fig. 21 illustrates a dimming control circuit according to some inventive
principles of this
patent disclosure. In this embodiment, the circuit is actuated by a PWM
dimming signal 200.
For example, the desired level of dimming can be set by the pulse of the PWM
dimming signal
200. The PWM dimming signal 200 is applied to the isolator 206. The isolator
206 bridges the
boundary 216 between voltage regions. In an embodiment, the PWM dimming signal
can be
located on a low voltage side of the boundary 216.
The isolator 206 is coupled to a resistor network 210. The resistor network
21.0 is also
coupled to an isolator 204 and a control node 214 coupled to a control input
of a transistor T2.
In an embodiment, the isolators 204 and 206 can be configured to be
substantially non-
conducting when a power supply is disabled. For example, as will be described
in further detail
below, the power supply can be a power supply in the low voltage region. Thus,
the isolators
204-and 206 can be substantially non-conducting when the low voltage region
power supply is
disabled. In particular, the PWM dimming signal 200 can be generated by
circuitry also
powered by the low voltage power supply. Accordingly, the isolators 204 and
206 can be
configured to be substantially non-conducting when the PWM dimming signal is
not a valid
signal.
The isolators 204 and 206 can be coupled to the resistor network 210 such that
when the
isolators 204 and 206 are substantially non-conducting, the direct current
(DC) current paths
associated with the control node 214 are substantially non-conducting. In
particular, as
described above, the isolators 204 and 206 can be substantially non-conducting
when the low
23
CA 02709513 2010-07-14
voltage power supply is disabled. As a result, the voltage on the control node
214 can remain
substantially the same after the low voltage power supply is disabled.
In this embodiment, the dimming circuit is configured to drive a dimming load
202
through output port 212. The dimming load 202 can be a pull-up style of load
where the control
is varied by varying the current pulled through the transistor T2. In
particular the current can be
varied by controlling the control node 214.
As described above, when the low voltage power supply is disabled, the control
node 214
can remain at substantially the same level. As a result, the current pulling
down the output port
212 can remain at substantially the same level. Thus the dimming load 202 can
receive
substantially the same signal even though a power supply associated with the
PWM dimming
signal 200 has been disabled.
Fig. 22 illustrates another dimming control circuit according to some
inventive principles
of this patent disclosure. In this embodiment optoisolator 220 is coupled
between a bias network
226 and the power supply terminal 228. The bias network 226 is coupled to the
power supply
terminal 224. Accordingly, when the power supply is disabled, the voltage drop
between the
power supply terminals 224 and 228 will not be sufficient to actuate the LED,
and hence, the
phototransistor.
Similarly, the optoisolator 222 is coupled to power supply terminal 224 and
driven by the
PWM dimming signal 200. When the power supply is disabled, the optoisolator
222 will
similarly be disabled. Although a bias network 226 has been illustrated for
only the optoisolator
220, a similar bias network could be used for optoisolator 222. Moreover, the
power supply 224
can supply a bias to the optoisolator 222 such that it can respond to the PWM
dimming signal
200. Regardless, when the power supply is disabled, the optoisolators 220 and
222 can be
configured to become substantially non-conducting.
In this embodiment, resistors R2 and R3 form a resistor network coupled to
control node
214. A capacitor C2 is coupled between the control node 214 and the output
port 212. As
illustrated, the only DC current paths from control node 214 are through the
phototransistors of
optoisolators 220 and 222. When the optoisolators 220 and 222 are disabled and
substantially
non-conducting, the DC current paths of the control node 214 are substantially
non-conducting.
Substantially non-conducting can, but need not mean that zero current will
flow from the
control node 214 when the optoisolators 220 and 222 are disabled. Rather, the
amount of current
24
CA 02709513 2010-07-14
that can flow is substantially reduced. For example, parasitic DC current
paths can charge or
discharge the control node 214. However, the components can be selected such
that a time frame
over which the voltage on the control node 214 changes can be controlled such
that the output
through the output port 212 can remain substantially the same for a desired
time period.
In addition, the capacitor C2 can aid in maintaining the output level. For
example, the
capacitor C2 can add additional charge storage to extend the time that the
level of the control
node 214 is substantially maintained. However, the capacitor C2 can also
provide feedback to
the control node 214. For example, if the output node 212 is pulled up,
control node 214 can be
similarly pulled up. As a result, the current through the transistor T2 can
increase, countering the
effects of the output node 212 being pulled up.
Although a transistor T2 has been described, other circuits with similar
properties can be
used. For example, additional transistors can be used to increase the output
drive capability.
Amplifier circuits can be used. Any circuit that can control a current in
response to the control
node 214 can be used.
Although a variety of circuits, systems, and the like have been described, any
combination of such circuits and systems can be combined within an electrical
switching
module. Moreover, although embodiments have been described with particular
implementations
of measuring circuits, zero-crossing detectors, or the like, an electrical
switching module can
include such circuits and can also include other conventional circuits.
.20 Fig. 23 illustrates an embodiment of a venting system for an electrical
switching
component according to the inventive principles of this patent disclosure. The
embodiment of
Fig. 23 includes an electrical switching component 1010 having an electrical
switching device
(not shown) substantially encapsulated in a case 1012. The case has a mounting
portion 1014,
which in this example is the bottom of the case 1012. The mounting portion
includes a vent
1016 to enable gases and other material from a blast to escape from within the
case. The
embodiment of Fig. 23 also includes a chassis 1018 having a mounting site 1020
where the
electrical switching device 1010 is mounted to the chassis. The mounting site
1020 includes a
passage 1022 to enable the blast from vent 1016 to flow from the case through
the chassis and
into a blast diverting space 1024.
Fig. 23 shows the electrical switching component 1010 elevated above the
chassis 1018
so as not to obscure the details of the mounting site 1020. When fully
assembled, however, the
CA 02709513 2010-07-14
electrical mounting portion 1014 of switching component 1010 is mounted to the
mounting site
1020 of the chassis 1018 so the vent 1016 is generally aligned with the
passage 1022.
The electrical switching device contained in the case is not shown in Fig. 23
so as not to
obscure the mounting portion 1014 or vent 1016. The electrical switching
device may be a relay,
a circuit breaker, a manually actuated switch, a dimmer, or any other type of
device or
combination of devices that controls current to a load and which, in, response
to electrical stress
such as a short circuit, over current condition, etc., or during normal
operation, may produce a
blast of gases, molten metal or any other matter that may damage or interfere
with the operation
of the device if not vented out of the case. A blast need not necessarily be a
high pressure event,
but may be, for example, a puff of ionized air generated by an arc caused by
opening a switch on
an inductive load.
The case 1012 may be of any suitable size, shape, material, etc., for
enclosing the specific
type of electrical switching device. Some examples of suitable materials
include various
plastics, composites, glasses, metals, etc. commonly used for encapsulating
relays, circuit
breakers, switches, etc. The case 1012 need not completely encapsulate the
electrical switching
device. For example, the case may include loose-fitting openings around
electrical terminals that
pass through the case, or there may be small gaps where different portions of
the case are joined,
or there may be imperfectly fit openings for access to potentiometers, dip
switches and the like.
Relatively small amounts of gas or other matter may escape from these openings
without
defeating the purpose of the vent 1016.
The vent 1016 may have any suitable form to vent gases or other material from
the case.
Some examples include a simple circular hole, a combination of holes to form a
baffle, a
pressure relief valve set to open only when the inside of the case reaches a
certain internal
pressure and/or temperature, a relatively thin or weak portion of the case
that ruptures under
pressure or high heat, an elastomeric material that opens to vent, but then
recloses after venting,
etc.
The mounting portion 1014 in the embodiment of Fig 21 is shown as a flat
bottom
portion of the case 1012 to enable the case to be attached to the flat
mounting site 1020 on
chassis 1018, but countless variations are contemplated by the inventive
principles of this patent
disclosure. For example, in some embodiments, the mounting portion may be
molded with a
profile to fit in or on a rail or track such as a standard DIN rail. In other
embodiments, the
26
CA 02709513 2010-07-14
mounting portion may be shaped to plug into a relay socket. In an embodiment
for a snap-in
type circuit breaker, the mounting portion may include the flat bottom of the
circuit breaker case
which is bounded at one end by a hook to engage the panel and at the other end
by the plug-in
terminal to engage the power distribution bus.
The manner in which the electrical switching component 1010 is attached to the
chassis
1018 is not limited to any particular technique and may depend on the
configuration of the
chassis 1018 and/or the mounting portion 1014 of the case 1012. In an
embodiment having two
flat mating surfaces as shown in Fig. 23, any type of fasteners such as
screws, rivets, clips,
adhesive etc. may be used. Either or both surfaces may have interlocking tabs,
slots, recesses,
protrusions, etc. In embodiments that utilize plug-in sockets, the case may be
held to the chassis
by the force of mating contacts and or tabs in the case. These forces may be
supplemented or
replaced by hold-down clips or other fasteners. As another example, in
embodiments that utilize
mounting rails or tracks, the mounting portion 1014 of the case 1012 may
simply slide into or on
the track or rail.
The chassis 1018 and mounting site are not limited to any particular
configurations,
although some specific examples are described below. In the embodiment of Fig.
23, the chassis
1018 is shown as a flat mounting plate that can be fabricated from metal or
any other suitable
material, and the mounting site 1020 is simply a portion of the plate matching
the footprint of the
case 1012. In some other embodiments, the chassis may be in the form of a rail
or a track in
which any portion of the rail or track may be designated as a mounting site.
In other
embodiments, the chassis may be a socket having a mounting site that includes
receptacles for
electrical terminals and/or tabs on the mounting portion of the case. In yet
other embodiments, a
printed circuit board may serve as the chassis with a mounting site that
includes drilled holes,
plated holes, etc. to receive the electrical switching component in the form
of a board mount
relay, circuit breaker, etc. The chassis may be a free-standing chassis, or it
may be mounted in,
or integral with, an enclosure.
The passage 1022 is shown as a simple circular hole in the embodiment of Fig.
23, but
the inventive principles contemplate many different forms. The passage may
include multiple
holes, channels, tubes, valves, etc. to direct the blast from the vent 1016 to
the blast diverting
space 1024. As with the vent 1012, the passage 1022 may be implemented as a
relatively weak
or thin portion of the chassis that ruptures under pressure or heat.
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CA 02709513 2010-07-14
The blast diverting space 1024 may be any suitable open or enclosed space. For
example, it may be specifically designed to receive the blast, or it may
utilize an existing space
in the chassis or an enclosure in which the chassis is mounted. The blast
diverting space may be
empty, or it may be fully or partially filled with material to absorb,
diffuse, cool, redirect, or
otherwise process the blast.
Figs. 24A and 24B (which may be referred to collectively as Fig. 24)
illustrate another
embodiment of a venting system according to the inventive principles of this
patent disclosure.
The embodiment of Fig. 24 is directed to a relay control panel that is housed
in a sheet metal
enclosure 1026. The electrical components are attached to a mounting plate
1028 which, as best
seen in Fig. 24B, is spaced apart from the back wall 1030 of the enclosure
1026 to form a space
1032 which is utilized as a blast chamber as described below. The mounting
plate 1028 may be
positioned relative to the back wall using spacers, folded sheet metal, or any
other suitable
technique.
Referring to Fig. 24A, the relay control panel may include any number of
relays 1034
which, in this example, are arranged in two rows on either side of low-voltage
control circuitry
1036. The low-voltage control circuitry may include a printed circuit board
having one or more
microprocessors, communication interfaces, timing circuits, interface
circuitry for photo sensors,
occupancy sensors and the like, as well as circuitry to drive the coils of
relays 1034. High
voltage wiring areas 1038 on either side of the enclosure 1026 provide space
for the connection
of line and load wires to the relay contact terminals. Though not shown, the
enclosure may
include a front panel to fully enclose the panel.
In the example embodiment of Fig. 24, the relays may have molded plastic cases
with
mounting portions implemented as flat bottom flanges that mount directly to
designated sites on
the mounting plate 1028 using any suitable attachment technique. High-voltage
connections
may be made to the relay contacts through spade-lug connectors or screw
terminals on the tops
of the relays, while low voltage connections may be made to the relay coils
through similar
terminals on the tops of the relays.
In other embodiments, the relays may be attached in the form of relay cards
having one
or more relays mounted on a printed circuit board along with terminal blocks
and other support
circuitry. Each relay card may have a terminal header to couple the card to
corresponding
28
CA 02709513 2010-07-14
terminals of the low voltage control circuitry 1036. The relay card may also
be attached to the
mounting panel with spacers, stand-offs, a sheet of insulated material, etc.
In the embodiment shown in Fig. 24B, each relay has a vent hole 1040 in the
bottom of
its case that aligns with a corresponding hole 1042 in the mounting plate
1028. In an
embodiment having relay cards, each printed circuit board may have a
corresponding hole that
aligns with both of the holes 1040 and 1042. Depending on the manner in which
the printed
circuit board is attached to the mounting plate, i.e., if the card is spaced
apart from the plate, a
tube or other apparatus may be included to direct the blast from the holes in
the relay and printed
circuit board to the hole in the mounting plate 1028.
As best seen in Fig. 24B, any blast from one of the relays 1034 is directed
into a blast
chamber 1032 formed between the mounting plate 1028 and the back wall 1030 of
the enclosure,
as well as a portion of the top wall 1044 and bottom wall 1046 and the side
walls 1048 and 1050
of the enclosure. A vent 1052 is located at the lower end of the mounting
plate 1028 and opens
the blast chamber into the main volume 1054 of the enclosure. Upon release
from the vent hole
1040, gases and/or other matter in a blast from relay 1034 is dispersed
throughout the blast
chamber 1032 and may eventually travel downward to vent 1052. If and when the
blast makes
its way through vent 1052 and into the main volume 1054 of the enclosure 1028,
it may have
dissipated enough to prevent damage or interfere with the operation of other
components located
within the enclosure. For example, hot exhaust gases may have cooled, ionized
air may have
become de-ionized, and molten metal may have solidified, clung to the back
wall of the
enclosure, or fallen to the bottom of the blast chamber.
The blast chamber 1032 may be empty, or it may be fully or partially filled
with a
material such as loose flame-resistant fiberglass insulation batting to
further contain the blast.
The embodiment of Fig. 24 may provide several benefits depending on the
implementation. For example, the system may require few, if any additional
components.
Electrical enclosures typically include mounting plates that are attached to
the back wall of the
enclosure with spacers or standoffs. A mounting plate is typically fabricated
by a stamping
operation in which the plate is cut to size and any necessary holes punched in
one stamping
operation. The additional holes for the vents may be fabricated in the same
stamping operation.
Likewise, the vent holes for the relays may be formed in the same molding
operation used to
create the relay case. Other than providing electrical isolation between
components on the
29
CA 02709513 2010-07-14
mounting plate and the back wall of the enclosure, the space between the plate
and the enclosure
may essentially be wasted space. Thus, at low additional cost, and perhaps
even no additional
cost, the embodiment of Fig. 24 may provide effective blast containment by
modifying existing
components and utilizing previously wasted portions of an electrical enclosure
to solve a
problem that has troubled panel designers for years.
Fig. 25 illustrates an embodiment of a relay 1056 according to some inventive
principles
of this patent disclosure. In the embodiment of Fig. 25, a relay circuit (not
shown) is
encapsulated in a molded plastic case 1058 having a flat mounting portion
1060. The flat
mounting portion includes tabs 1062a-62d which form an enlarged flange at the
bottom of the
relay for attachment to a generally flat mounting site on a chassis. Slots
1064a, 1064b are
formed between the tabs on either side of the flange to accommodate screws or
other fasteners to
attach the relay to the chassis. Electrical connections are made to the relay
through terminals
1066a, 1066b which protrude through the top of the case 1058. A vent hole 1068
enables gases
or other material to escape from within the case 1058. The vent hole 1068 may
be sized and
located to align with a corresponding passage in the mounting site of the
chassis. Although not
limited to any particular application, the embodiment of Fig. 25 may be suited
for use in the
embodiment of the relay panel of Fig. 24.
Fig. 26 illustrates an embodiment of a relay card according to some inventive
principles
of this patent disclosure. The relay card 1070 of Fig. 26 includes a relay
1072 having a case 1074
with a mounting portion 1076, which in this example is the bottom of the case
1074. The
mounting portion includes a vent 1078 to enable gases and other material from
a blast to escape
from within the case. The relay 1072 is attached to PC board 1080 at a
mounting site 1082
which includes an additional passage or vent 1084 to enable the blast to pass
through the printed
circuit board. -A terminal header 1086 on the bottom of the PC board engages
terminal pins on a
control PC board to couple the relay coil and other circuitry on the relay
board to low-voltage
control circuitry on a control PC board, or to other control circuitry. A
terminal block 1088
enables high-voltage wiring to be connected to the contacts of the relay 1072
through traces on
the PC board. Connections to the relay are through terminals (not visible in
this view) on the
bottom of the case 1074 which may be soldered to contacts, plated holes, etc.,
on the PC board.
The relay card 1070 of Fig. 26 maybe mechanically supported at one end by the
terminal.
header 1086 and at the other end by a standoff attached to a mounting hole
1090. If the terminal
CA 02709513 2010-07-14
card of Fig. 26 is used in a system such as the relay panel shown in Fig. 24,
the blast from vents
1078 and 1084 may be further directed through a corresponding hole 1042 in the
mounting plate
1028. A tube or other blast directing device may be included between the PC
board and the
mounting plate to form a continuous passage between vents 1078 and 1084 and
hole 1042 in the
mounting plate 1028.
Fig. 27 illustrates another embodiment of a venting system according to some
inventive
principles of this patent disclosure. The embodiment of Fig. 27 includes a
relay 1092 similar to
the relay 1072 of Fig. 26. Rather than being mounted to a PC board, however,
the relay 1092 is
mounted in a plug-in relay socket 1094. Though not shown in Fig. 27,
electrical and mechanical
connections are made through terminal pins or spades that protrude from the
bottom mounting
portion 1096 of the relay 1092 and extend through openings in a mounting site
1098 of the
socket to engage receptacles in the socket. The socket 1094 also includes a
bottom mounting
portion 1100 that mounts to a mounting site 1102 on a plate 1104 or other
additional chassis.
In the embodiment of Fig. 27, the socket 1094 is formed with a through-passage
1106 to
connect vent 1108 in the bottom of the relay 1092 with a passage 1110 in the
plate 1104. This
provides a continuous passage to channel a blast from the relay through the
socket and plate and
into a blast chamber 1112. In an alternative embodiment, the socket itself may
include a blast
chamber, in which case, the bottom of the socket may be closed, or have a
reduced aperture to
enable only a portion of the blast to pass through the socket and plate.
Fig. 28 illustrates another embodiment of a venting system according to some
inventive
principles of this patent disclosure. The embodiment of Fig. 28 includes a
mounting track or rail
1114 such as a standard DIN mounting rail. An electrical switching component
1116 includes a
case 1118 having a mounting portion 1120 with a vent 1122. The case is secured
to the rail 1114
by rail-engaging members 1124a, 1124b. The mounting site is simply the portion
of the rail on
which the case is mounted. In this embodiment, the rail may serve as a blast
chamber, either
alone, or by directing the blast to one or more additional blast diverting
spaces. Thus, the
interior cavity of the rail may be filled with blast-absorbing material.
Fig. 29 is a cross-sectional view illustrating another embodiment of an
electrical
switching component according to some inventive principles of this patent
disclosure. In the
embodiment of Fig. 29, a relay is housed in a case 1126 having at least two
chambers. A first
chamber 1128 contains a pair of contacts 1132a,132b, or other switching
element, electrically
31
CA 02709513 2010-07-14
connected to terminals 1134a,134b that extend through the case 1126. A vent
1142 enables a
blast from the contacts, for example from an overload or short circuit
condition, to escape from
the first chamber. The first chamber may include other openings, provided a
substantial portion
of a blast is directed through vent 1142. In some embodiments, the portion of
the case having
the vent 1142 may be a mounting portion, which may also include the terminals
1134a, 1134b.
A second chamber 1130 includes a solenoid 1136 or other actuating device to
actuate the
contacts using a plunger 1138 that passes through a chamber wall that
separates the first and
second chambers. The second chamber 1130 also includes electronics 1140 to
control the
operation of the relay and communicate with external components such as a
controller.
Placing the contacts 1132a, 1132b in a separate chamber may protect the
components in
the second chamber from a blast from the contacts. The second chamber need not
be totally
enclosed, but may simply be separated enough from the first chamber to
substantially protect
components in the second chamber from a blast in the first chamber.
Countless variations of this embodiment are possible according to some of the
inventive
principles of this patent disclosure. In the example of Fig. 29, there are two
chambers, but other
configurations having different numbers of chambers are contemplated. Some
variations may
include locating the relay coil in the first chamber or a third chamber. In
other embodiments,
additional sets of contacts may be located in the first chamber, or the
additional contacts may be
located in a third chamber, fourth chamber, etc., to prevent a blast from one
set of contacts from
interfering with the operation of the other contacts. The additional chambers
may have
additional vents which may be located in the same mounting portion as the
first vent, in a
different mounting portion of the case, or in a non-mounting portion of the
case.
Fig. 30 is a partially exploded perspective view illustrating an embodiment of
a relay
assembly having a venting system according to some inventive principles of
this patent
disclosure. The embodiment of Fig. 30 illustrates a two-pole assembly, meaning
that two
different relays for switching two different circuits are included in one
case. The case includes
two side shells 1144a and 1144b, each of which houses one of the relays. In
this view, only the
left-side relay 1146a is visible. Abulkhead 1148 divides the entire case in
half so that a blast on
one side does not interfere with the operation of the circuitry on the other
side. The case also
includes a base plate 1150 to mount the relay assembly to a mounting site on a
plate, channel, or
other suitable apparatus.
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CA 02709513 2010-07-14
Connections to the contacts of the left-side relay 1146a are through
conductors 1152a and
1154a. External wires may be connected to the conductors by screw terminals
(not shown)
attached to the conductors. Apertures 1156a and 1158a allow the wires to be
inserted into the
terminals, while apertures 1160a and 1162a provide screwdriver access to the
terminals.
Connections to the relay solenoid and/or control electronics may be made
through header pins,
terminal blocks, wire leads or any other suitable arrangement. In the example
of Fig. 30, the
relay 1146a is mounted to a printed circuit board 1164 which includes header
pins (not visible in
this view) to provide connections through the case to the relay solenoid
and/or control electronics
on the circuit board. A slider plate 1166 moves manual override actuators
simultaneously on
both relays in response to motion of a manual actuator 1168 which protrudes
through an opening
in the case.
In the event of a blast from relay 1146a, another bulkhead 1170 prevents the
blast from
exiting the terminal apertures 1156a-162a (which may damage the external
wires) and instead
directs the blast through a vent 1172a in the base plate 1150. Another vent
1172b (not visible in
this view) is arranged in a similar location on the other side of the base
plate to vent a blast from
the relay 1146b on the other side of the case.
Relay 1146a may be an open frame device, or it may be contained within another
(inner)
case as shown here. The inner case may have a single chamber, or it may have
multiple
chambers as described above in the context of Fig. 29. The inner case may be
designed to
20. rupture in the event of a blast, in which case the gases and/or other
material from the blast flow
through the open spaces within the outer case 1144a, 1144b, 1150 until they
are directed to the
vent 1172a. In some embodiments, additional bulkheads, passages, baffles, etc.
may be arranged
within the outer case to channel the blast to the vent. Alternatively, the
inner case may be
designed to expel a blast in a more controlled manner. For example, the inner
case may include
a vent in a mounting portion, or any other portion, which may be oriented to
direct a blast in the
general direction of the vent 1172a, either directly through any open space in
the outer case, or
through a system of additional bulkheads, passages, baffles, etc.
Fig. 31 is a perspective view showing the opposite side of the embodiment of
Fig. 30. In
the view of Fig. 31, both of vents 1172a and 1172b are visible in the base
plate 1150, and both
case shells 1144a and 1144b are shown in their assembled positions. A right
angle header 1174
is shown in the position it is in when the header pins for the
solenoid/control connections are
33
CA 02709513 2010-07-14
fully engaged with the header. The right angle terminals extending from the
header 1174 may be
soldered to a circuit board (not shown) on which control circuitry is located.
For example,
control circuitry 1036 shown in Fig. 24A may be interfaced to the embodiment
of Fig. 31
through header 1174. Another connector 1176 may be included to provide
additional or
alternative mechanical and/or electrical connections to the relay assembly.
In the embodiment of Fig. 31, the base plate 1150 includes mounting ears 1178
and 1180
which may pass through apertures in a mounting plate and engage the plate to
secure the relay
assembly to a mounting site on the plate when the relay assembly is slid in
the direction of
arrow A. This sliding action may also cause the terminal pins to engage in
header 1174, and may
additionally cause connector 1176 to engage the case of the relay assembly.
The vents 1172a
and 1172b are located relative to mounting ear 1178 such that, after the
mounting ear passes
through an aperture on the mounting plate and the relay assembly is slid into
position in the
direction of arrow A, the aperture is then positioned over the vents to enable
the vents to
communicate with the space on the other side of the mounting plate. Thus, the
one aperture in
the mounting plate operates synergistically as both a passage to vent a blast,
and an aperture to
engage the mounting ear 1178.
Although the example embodiment of Figs. 30 and 31 is shown as a two-pole
relay
assembly, other embodiments may be realized with relays, circuit breakers, or
other switching
devices, and with any number of poles, e.g., single pole, three-pole, etc.
Moreover, any number
of switch states or positions may be used, for example, single throw, double
throw, etc.
Fig. 32 is a perspective view illustrating an electrical switching device
according to some
inventive principles of this patent disclosure. In this embodiment, the
electrical switching device
1200 includes a case 1202, contacts 1204 and 1206, a manual actuator 1210, and
a solenoid
1212. A wall 1216 within the electrical switching device substantially
separates the contacts
1204 and 1206 within the case 1202 from the manual actuator 1210 and the
solenoid 1212. The
contacts 1204 and 1206 are coupled to terminals 1208 and 1209.
Although the electrical switching device 1200 is illustrated apparently as a
cutaway view,
in an embodiment, the electrical switching device 1200 can have an open side.
For example, the
case 1202 can be configured to include less than all sides to encapsulate the
internal components.
That is, the electrical switching device 1200 can be manufactured with the
contacts 1204 and
1206, solenoid 1212, or the like within the case 1202 exposed. In another
embodiment, the
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CA 02709513 2010-07-14
electrical switching device 1200 can be configured with a wall enclosing the
contacts 1204 and
1206, solenoid 1212, or the like. The electrical switching device 1200 can be
configured that
such a wall is removable. For example, the electrical switching device 1200
can be an off-the-
shelf component. In particular, the electrical switching device can be an off
the shelf component
substantially lacking in structures to guide a blast. That is, a blast could
exit from the case 1202
of such an off-the-shelf electrical switching device 1200 in an undetermined
location on the case
1202. However, by removing a lid, wall, side, or the like of such an
electrical switching device
1200, a blast can be guided as will be described in further detail below.
Regardless, the electrical
switching device 1200 includes an opening in the case 1202 that is configured
to expose the
contacts 1204 and 1206.
Although an opening in the case 1202 has been illustrated as including
substantially all of
one side of the electrical switching device 1200, the opening can include more
or less of the case
1202. For example, in an embodiment, the case 1202 can include an opening that
only exposes
the contacts 1204 and 1206 within the case. In other words, the manual
actuator 1210, the
solenoid 1212, or the like within the case 1202 may not be exposed through the
opening. In
another embodiment, multiple sides of the electrical switching device 1200 can
expose the
internal components.
Although a particular type of electrical switching device has been described,
namely an
electrical switching device 1200 with a solenoid 1212 actuator, any actuator
can be used. In
addition, the electrical switching device 1200 can be any switching device as
described above.
Fig. 33 is a cutaway view illustrating a duct according to some inventive
principles of this
patent disclosure. In this embodiment, a case can be arranged to substantially
encapsulate the
electrical switching device 1200. A side 1234 of the case is illustrated. The
electrical switching
device 1200 is disposed in contact with the side.
In the following description, various portions of an electrical switching
device assembly
will be described. However, portions that may have been previously described
or portions that
will be described later may or may not be illustrated. The illustrations may
omit some portions
for the sake of clarity.
The side 1234 includes at least one duct 1230. A duct 1230 includes one or
more
structures that form an opening. The duct 1230 is disposed adjacent to the
electrical switching
device 1200. In particular, the duct 1230 is disposed adjacent to the opening
in the electrical
CA 02709513 2010-07-14
switching device 1200. Accordingly, as the opening is disposed to expose the
contacts 1204 and
1206 of the electrical switching device 1200, any blast from the contacts 1204
and 1206 can
enter the duct 1230.
In this embodiment, a rib 1232 can be disposed in the ducts. The rib 1232 can
be
disposed in the duct 1230 such that the duct 1230 has additional structural
support. For example,
the rib 1232 can increase a stiffness of the side 1234 in the duct 1230. In an
embodiment, the
duct 1230 can be formed from a recessed region of the side 1234. The recessed
region can be
strengthened by ribs 1232. Although one rib 1232 has been described, in an
embodiment,
multiple ribs 1232 can be disposed in the duct 1230 as desired.
In another embodiment, the rib 1232 can be configured to. contact the case
1202 of the
electrical switching device 1200. As a result, the rib 1232 can provide an
amount of support to
the case 1202. Moreover, in an embodiment, the rib 1232 can but need not be
aligned
substantially parallel to an axis of the case 1202. For example, the rib 1232
can be disposed at
an angle, such as at an angle directed towards a vent. Thus, the rib 1232 can
be configured to
guide a blast from the electrical switching device 1200.
In another embodiment, the side 1234 can include a bulkhead 1233. The bulkhead
1233
is disposed extending from a top 1235 of the side 1234 to the case 1202. As
described above, the
duct 1230 can guide a blast from the electrical switching device 1200.
However, once the blast
exits the electrical switching device 1200, the blast can expand through any
available opening.
The bulkhead 1233 can be configured to substantially isolate other electrical
circuitry from the
blast. That is, the bulkhead 1233 can guide the blast away from travelling
around the case 1202.
. Fig. 34 is a cross-sectional view illustrating an example of an interface of
the electrical
switching device and case of Fig. 33 along cross-section 1231. The case 1202
of the electrical
switching device 1200 is in contact with the side 1234 of the case. Where the
case 1202 contacts
the side 1234, the side .1234 can include walls 1236 and 1238. The walls 1236
and 1238 can be
disposed to contact a perimeter of the case 1202. Although walls of the side
1234 have been
described, in an embodiment, the perimeter of the case 1202 can contact the
surface of the side
1234. That is, the side 1234 need not have distinguishable walls to contact
the case 1202.
However, the case 1202 and the side 1234 can still be in contact to aid in
guiding a blast.
Accordingly, the contact of the case 1202 and the side 1234 forms the duct
1230. Gasses,
particles, or the like from a blast can be exhausted through the duct 1230. In
particular, in an
36
CA 02709513 2010-07-14
embodiment, the case 1202 of the electrical switching device 1200 can form an
expansion
chamber coupled to the duct 1230. As will be described in further detail
below, the duct 1230
can open on to such an expansion chamber. The blast can be guided into the
expansion chamber
where the gases can expand and cool.
Fig. 35 is an exploded cutaway view of the embodiment of Fig. 33. In this
view, the
electrical switching device 1200 is illustrated as offset from the side 1234
to expose the wall
1240. The wall 1240 of the side 1234 can be disposed within the case 1202 of
the electrical
switching device 1200.
That is, in an embodiment, the wall 1240 can be configured to extend into the
case 1202
of the electrical switching device. The wall 1240 can be configured to be
disposed adjacent to
the wall 1216 of the case 1202. Accordingly, the wall 1216 of the case and the
wall 1240 of the
side 1234 can function as a bulkhead to contain a blast from the contacts 1204
and 1206.
Additional walls can also contact the case 1202. For example, the walls 1236,
1238, and
1246 of the side 1234 and the corresponding perimeter of the case 1202 of the
electrical
switching device 1200 form additional walls. The case 1202 can provide
additional walls. Such
walls can substantially contain a blast.
However, because of the interface between the case 1202 and the duct 1230,,an
opening
remains to guide the blast from the chamber 1244. As a result, the blast can
be guided away
from the electrical switching device 1200.
Fig. 36 is a cross-sectional view illustrating an example of an interface of a
wall of the
case and a wall of the electrical switching device. As described above, a wall
1216 can separate
the contacts 1204 and 1206 from other components of the electrical switching
device 1200, such
as the solenoid 1212. The wall 1240 of the side 1234 extends into the
electrical switching device
1200. In this embodiment, the wall 1240 partially extends into the electrical
switching device
1200. However, in other embodiments, the wall 1240 can fully extend to the
opposite side of the
electrical switching device 1200. In another embodiment the wall 1240 can form
a butt joint.
That is, the wall 1240 of the side 1234 and the wall 1216 of the electrical
switching
device 1200 form a wall of a chamber 1244. Accordingly, a blast from contacts
1204 and 1206
can be guided substantially in a desired direction. Accordingly, any blast
from the contacts 1204
and 1206 can be substantially prevented from traveling towards the solenoid
1212 or other
electronics. The blast can be guided through the duct 1230.
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CA 02709513 2010-07-14
In an embodiment, the duct 1230 can be the only opening exposing the chamber
1244 to
a region external to the electrical switching device 1200. For example, the
contact of the walls,
the case 1202, and the like can be sealed together. Adhesives, welding,
gaskets, or the like can
seal the surfaces together. As a result, the only route for expanding gas and
particles from the
blast is through the duct 1230.
In another embodiment, the duct 1230 can be sized such that a majority of the
blast is
directed through the duct 1230. For example, there can be some opening between
the wall 1216
of the electrical switching device 1200 and the wall 1240 of the side 1234.
Other interfaces,
such as the interface of the walls 1236 and 1238 to the perimeter of the
electrical switching
device 1200 can also have similar gaps, openings, or the like. As a result, a
portion of the blast
can escape beyond the junction of the walls.
However, the duct 1230 can be sized such that a cross-sectional area of an
opening
created in the duct 1230 between the side 1234 and the electrical switching
device 1200 can be
greater than a combination of similar cross-sectional areas of the gaps,
openings, or the like
described above. As a result, even though it is possible for the blast to
escape through the other
openings, a majority of the blast can escape through the duct 1230.
As illustrated in Fig. 36, the wall 1240 can be a planar wall. As illustrated
in Fig. 35, the
wall 1240 can include multiple walls. Accordingly, the wall 1240 can take any
variety of
configurations. That is, the wall 1240 can be disposed on the solenoid 1212
side of the wall
1216. In another embodiment, the wall can straddle the wall 1216. In another
embodiment, the
wall 1240 can be disposed on the contact 1206 side of the wall 1216.
Fig. 37 is an exploded cutaway view illustrating a bulkhead according to some
inventive
principles of this patent disclosure. Fig. 38 is an exploded cutaway view of
the embodiment of
Fig. 38 from a different angle. Referring to Figs. 37 and 38, in an
embodiment, a first bulkhead
1258 can extend between an electrical switching device 1200 and a second
bulkhead 1252.
In this embodiment, the first bulkhead 1258 is part of a center bulkhead 1254
dividing the
electrical switching component. When the center bulkhead 1254 is assembled
with the side
1234, the bulkhead 1258 is disposed between the electrical switching device
1200 and the second
bulkhead 1252.
In an embodiment, the second bulkhead 1252 is a circuit board. However, the
second
bulkhead 1252 need not be a circuit board. For example, in an embodiment, the
second bulkhead
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CA 02709513 2010-07-14
1252 can be a bottom 1250 of the electrical switching component, the side
1234, or the like.
Thus, the bulkhead 1258 can extend from the electrical switching device 1200
to the bottom
1250 of the electrical switching component. In another embodiment, the second
bulkhead 1252
can be another internal structure of the electrical switching component.
Similar to the bulkhead
1233 described above, the bulkhead 1258 can substantially isolate other
electrical components
from the blast by guiding the blast away from the side of the case 1202.
Fig. 39 is a cutaway view illustrating a circuit board in the assembly of Fig.
38 according
to some inventive principles of this patent disclosure. In this view, the
center bulkhead 1254 is
assembled with the side 1234. The center bulkhead 1254 can include a duct
1230, a wall 1240,
and the like similar to the side 1234. Accordingly, a second electrical
switching device (not
illustrated) similar to the electrical switching device 1200 described above
can be assembled
with the center bulkhead. A bulkhead 1256 can extend from the electrical
switching device to
the bulkhead 1252.
In addition to guiding the blast, the various bulkheads can isolate other
electrical circuitry
from the blast. As described above, a blast can travel through duct 1230. The
blast can expand
towards the circuit board 1252. The blast can be blocked by the circuit board
1252.
Accordingly, electrical components, and in particular, electrical components
that are electrically
coupled to lower voltage circuitry, can be protected from the blast.
Although the bulkhead 1256 has been illustrated as substantially in line with
the wall
1240, the bulkhead 1256 can be disposed in other locations. For example, the
bulkhead 1256 can
be disposed further away from the ducts 1230. Additional walls such as the
wall 1242 can
contact the perimeter of the case 1202 of the electrical switching device
1200. Accordingly,
other components including the components of the electrical switching device
1200 can be
substantially isolated from the blast.
Although the duct 1230 has been illustrated as disposed on the center bulkhead
1254, the
duct 1230 can be disposed in other locations. In an embodiment, the duct 1230
can be disposed
on another side (not illustrated) of the electrical switching component
opposite the side 1234. In
another embodiment, the ducts for multiple electrical switching devices 1200
can be disposed on
the center bulkhead 1254. The openings of the electrical switching devices
1200 can be disposed
to open on to the duct 1230, regardless of the particular location.
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CA 02709513 2010-07-14
Fig. 40 is a cutaway view illustrating a circuit board according to some
inventive
principles of this patent disclosure. In this embodiment, the circuit board
1252 is mounted to the
side 1234 and the bottom 1250. The circuit board 1252 can be similarly mounted
on another side
of the case (not illustrated). The circuit board 1252 is supported by stand-
offs 1270 and 1272.
The stand-offs 1270 and 1272 can be configured to offset the circuit board
1252 from the bottom
1250. As a result, circuitry can be disposed on side 1255 of the circuit board
1252.
In addition to supporting the circuit board 1252, the stand-off 1270 can
substantially
isolate the opposite side 1255 of the circuit board 1252. For example, the
blast can be directed
along the circuit board 1252. The stand-off 1270 can also be configured to
direct such a blast
away from the opposite side 1255 of the circuit board 1252.
Fig. 41 is the cutaway view of Fig. 40 without the circuit board. Supports
1280 and 1282
can be configured to support an edge of the circuit board 1252. For example,
the circuit board
1252 can be disposed between the supports 1280 and 1282.
The supports 1280 and 1282 can extend along a length of the circuit board
1252. In
particular, in an embodiment, the support 1280 can extend along a length of
the circuit board
1252. Accordingly, when a blast increases the pressure on the circuit board
1252, the circuit
board 1252 can be pressed on to the support 1280. Thus, the blast can be
substantially prevented
from escaping around an edge of the circuit board extending along the length.
The support 1280 can, but need not extend along the entire length of the
circuit board
1252. For example, the support can extend only along a length of the circuit
board 1252 where
the circuit board 1252 may encounter a blast. Similarly, the support 1282 can,
but need not
extend along an entire length of the circuit board 1252. For example, the
support 1282 can
include periodically spaced supports along the edge. Although the support 1280
has been
illustrated as continuous along a length of the circuit board 1252, the
support 1280 can include
periodically spaced structures.
The supports 1280 and 1282 have been illustrated for an example. Other
supports can be
included on another side of the case, a center bulkhead 1254, or the like.
Accordingly, along a
perimeter of the circuit board 1252, the edges of the circuit board 1252 can
be substantially
sealed. However, in an embodiment, the edges of the circuit board can, but
need not be
substantially sealed beyond a bulkhead, such as bulkhead 1256 or 1258. That
is, if the blast is
CA 02709513 2010-07-14
substantially isolated from a region of the circuit board 1252, the edges in
that region need not be
substantially sealed.
Moreover, although the supports 1280 and 1282 have been illustrated as
protrusions, the
supports 1280 and 1282 can take different forms. For example, the supports
1280 and 1282 can
include a slot, recessed region of the side 1234, or the like configured to
receive an edge of the
circuit board 1252. Any combination of such protrusions and recessed regions
can be used.
Fig. 42 is a cutaway view illustrating a bulkhead and terminals according to
some
inventive principles of this patent disclosure. In this embodiment, a second
electrical switching
device 1200 is illustrated as assembled on the center bulkhead 1254. The
contacts of the
electrical switching device 1200 are coupled to conductors 1294. The
conductors 1294 are
coupled to corresponding terminals 1290. The terminals 1290 can be configured
to be coupled to
wiring 1292.
Although the terminals 1290 have been illustrated as screw terminals, the
terminals 1290
can have a variety of configurations. For example, the terminals 1290 can be
quick-connect
terminals, connectors, or the like.
A blast from the electrical switching device 1200 can travel through the
chamber
including the conductors 1294. However, a bulkhead 1296 can be disposed
between the
electrical switching device 1200 and the terminals 1290. The conductors 1294
can be disposed
to extend through the bulkhead where the bulkhead 1296 can be configured to
substantially
isolate the terminals 1290 from a blast.
As illustrated in Fig. 42, the bulkhead 1296 is part of the center bulkhead
1254.
However, a gap 1295 can be present in the bulkhead 1296 to allow for placement
of the
conductors 1294. The gap 1295 can be substantially filled by a corresponding
structure on
another side (not illustrated) of the electrical switching component.
Accordingly, although the
bulkhead 1296 has been described as substantially isolating the terminals 1290
from a blast, the
isolation can include a contribution from the additional structure of the
other side. Moreover,
although the bulkhead 1296 has been illustrated as an internal bulkhead, the
bulkhead 1296 can
be formed from a side of the case, such as side 1234. That is, in an
embodiment, the bulkhead
1296 can be a wall of the case.
Fig. 43 is the cutaway view of Fig. 42 rotated to illustrate a vent according
to some
inventive principles of this patent disclosure. As described above, a vent
1300 can be disposed
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CA 02709513 2010-07-14
in the case to allow a blast to vent to outside of the case. In this
embodiment, the vent 1300 is
disposed between the electrical switching device 1200 and the bulkhead 1296.
However, in
other embodiments, the vent 1300 can be disposed anywhere such that there is a
substantially
continuous path between the electrical switching device 1200 and the vent.
Accordingly, a blast can occur in the electrical switching device 1200. The
blast can be
guided through the ducts 1230. The ducts 1230 can vent into the chamber
defined by the center
bulkhead 1254, the circuit board 1252, the bulkhead 1256, the bulkhead 1296,
and the other side
(not illustrated). As the chamber is larger than the chamber 1244 of the
electrical switching
device 1200, the blast can expand, reducing the temperature and pressure. The
gap between the
stand-off 1270 and the bulkhead 1296 directs the blast towards the vent 1300
and towards an
exterior of the electrical switching component.
Similar to the size of the duct relative to the size of any opening created by
the junction
of the case 1202 of the electrical switching device 1200 and the side 1234,
the size of the vent
1300 can be selected such that a cross-sectional opening of the vent 1300 is
larger than a
combination of other gaps, openings, or the like between the various sides,
circuit board,
bulkheads, and the like guiding the blast. Accordingly, a substantial amount
of the blast can be
guided out of the vent 1300.
In an embodiment, the electrical switching component can include multiple
bulkheads
disposed between the electrical switching device 1200 and the terminals 1290.
As illustrated in
Fig. 43, the conductor 1294 extends through bulkhead 1297. In this embodiment,
only one of the
conductors 1294 passes through a bulkhead 1297 in addition to the bulkhead
1296. However, in
other embodiments, the other conductor 1294, each of the conductors 1294, or
the like can pass
through multiple bulkheads between the electrical switching device 1200 and
the terminals 1290.
In an embodiment, the conductor 1294 that is furthest from the vent 1300 can
pass
through bulkhead 1297. A blast guided by the ducts 1230 and directed towards
the bulkhead
1297 may not have fully expanded and could have a pressure high enough to blow
past an
interface of the conductor 1294 and the bulkhead 1296. However, the bulkhead
1297 can
redirect the blast such that the blast can further expand, reduce in pressure,
temperature, or the
like, before the blast reaches an interface exposing the outside of the
electrical switching
component. That is, the shock front of the blast can be guided such that
pressure is reduced
before the blast has an opportunity to escape the electrical switching
component.
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CA 02709513 2010-07-14
Moreover, in an embodiment, the bulkhead 1297 can create a substantially
separate
chamber 1299. The chamber 1299 can be formed from a curvature of the bulkhead
1297 towards
the bulkhead 1296. Other structures such as the center bulkhead 1254 or the
like can create other
sides of the chamber 1299. Accordingly, a blast must travel through multiple
chambers,
experiencing an expansion out of the duct 1230, a constriction when passing
through a gap 1287,
another expansion in chamber 1299, and so on. Multiple chambers such as
chamber 1299 can be
created such that a blast travelling towards the terminal 1209 can experience
such expansions
and constrictions. As a result, the interfaces of the sides, bulkheads, walls,
or the like can be
more likely to contain the blast and guide it to the intended vent 1300.
In an embodiment, a sealant, such as a silicone based sealant, or other
sealants, can be
used between bulkheads, components, or the like, where such components meet.
For. example, a
room temperature vulcanizing (RTV) silicone rubber sealant can be added
between the conductor
1294 and the bulkheads 1291 and 1297. In another example, a sealant can be
added between
bulkheads 1254 and bulkhead 1297. Furthermore, although a sealant can be added
between all
bulkheads and components, a sealant can omitted from some joints, for example,
to provide a
lower resistance path for a blast.
Fig. 44 is a cross-sectional view illustrating a second chamber according to
some
inventive principles of this patent disclosure. Fig. 45 is a cross-sectional
view along plane 1298
illustrating a wall of the second chamber of Fig. 44 according to some
inventive principles of this
patent disclosure. In the embodiment of Fig. 43, the bulkheads 1299 and 1296
are illustrated as
including gaps 1287 and 1295 allowing the conductor 1294 to be assembled in
the electrical
switching component. In contrast, in the embodiment of Fig. 44, the
corresponding gaps are on
opposite sides of the conductor 1294.
For example, the center bulkhead 1254 includes the bulkhead 1296. The bulkhead
1296
extends towards the side 1234. As described above, a gap 1295 is present to
allow assembly. A
tab 1291, illustrated in phantom, can substantially fill the gap 1295,
substantially sealing that
wall of the chamber 1299. In contrast, the gap 1287 of the bulkhead 1297 is
disposed on an
opposite side of the conductor 1294. Moreover, the bulkhead 1297 is disposed
on the side 1234,
not on the center bulkhead 1254 as illustrated in Fig. 43. A tab 1291 of the
center bulkhead 1254
extends to fill the gap 1297 of the bulkhead 1297.
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CA 02709513 2010-07-14
The cross-sectional view along plane 1289 is illustrated for bulkhead 1297.
However, the
orientation of the gap 1295 and the bulkhead 1296 are on opposite sides for a
similar cross-
section. A blast can escape through the gaps in such structures. However, a
blast travelling
along conductor 1294 will not have a substantially straight path through
chamber 1299. That is,
because of the orientation of the gaps, the blast can change direction,
deposit suspended particles
on the walls, and further isolate the terminal 1290 and any wiring from the
blast.
Fig. 46 is a block diagram illustrating an example of guiding a blast
according to some
inventive principles of this patent disclosure. In this embodiment various
components described
above are conceptually illustrated to show a path traveled by a blast. A case
1202 of an electrical
switching device 1200 includes the contacts 1204 and 1206 where a blast
occurs. Walls 1216
and 1240 contain the blast and, with the case 1202, guide the blast through
the ducts 1230 into an
expansion chamber 1298.
The chamber 1298 is bounded by the center bulkhead 1254, a corresponding side
such as
side 1234, bulkhead 1296, bulkhead 1256 or 1258, circuit board 1252, and stand-
off 1270. In
one example, a blast can be deflected by the center bulkhead 1254 or side
1234, directed towards
the vent 1300 by bulkhead 1298. In another example, the blast can be deflected
by walls 1256 or
1258, and circuit board 1252 towards the vent 1300. Accordingly, in an
embodiment, each of the
various walls, bulkheads, circuit boards, and the like contribute to
containing the blast and
guiding it towards the vent 1300.
Moreover, in an embodiment, the electrical switching component can form a
module.
That is, the electrical switching device 1200, which has its own case 1202,
can be encapsulated
within the case formed by the various walls, bulkheads, and the like described
above to form a
modular component.
Fig. 47 is a block diagram illustrating various zones according to some
inventive
principles of this patent disclosure. As described above, walls 1256 and 1258,
and stand-off
1270 can substantially isolate portions of the circuit board 1252 from a
blast. Fig. 47 illustrates a
top view of the circuit board 1252. Walls 1256 and 1258 can divide the circuit
board 1252 into
two different zones 1301 and 1302.
Zone 1301 can be a high voltage circuit zone. That is, high voltage circuitry,
relays,
switches, or the like can be disposed in circuit zone 1301. For example,
various components that
may be coupled to the electrical switching device 1200, the conductors 1294,
or the like within
44
CA 02709513 2010-07-14
the electrical switching component can be coupled to the circuit board 1252 in
zone 1301. In
addition, circuit zone 1301 can include the portion of the circuit board 1252
that can deflect a
blast as described above. Accordingly, as a blast can create short circuits
between a line terminal
of the electrical switching component, circuitry within the zone 1301 could be
subjected such
line voltages. Accordingly, the circuitry in zone 1301 could be exposed to a
voltage range
including high voltages.
In contrast, circuit zone 1302 can be substantially isolated from the blast.
As described
above, the walls 1256 and/or 1258 can prevent an amount of the blast from
reaching circuitry
within zone 1302. Accordingly, the circuitry in zone 1302 can be exposed to a
voltage range
including maximum voltages lower than that of circuit zone 1301. That is, even
after a blast,
short circuits caused by the blast may not cause high voltages to be conducted
to circuitry in
zone 1302. Thus, low voltage circuitry, processors, interfaces, or the like
can be placed in zone
1302.
Fig. 48 is a block diagram illustrating additional zones of the circuit board
of Fig. 47
according to some inventive principles ofthis patent disclosure. Fig. 46
illustrates the opposite
side of circuit board 1252. Walls 1256 and 1258 are illustrated in phantom for
reference.
This side of the circuit board 1252 includes zones 1305 and 1306. The zones
1305 and
1306 can be divided by an isolator 1303. The isolator 1303 can form a division
1307 between
the zones 1305 and 1306. The isolator 1303 can be a variety of devices. For
example, the
isolator 1303 can be an opto-isolator, a transformer, or the like such that
current is substantially
prevented from flowing directly across the isolator 1303.
In zone 1305, circuitry can be present that does not operate in the high
voltage range of
zone 1301. However, zone 1305 can include through-hole components that
penetrate the circuit
board 1252. As a result, the components can have electrical contact with zone
1301 on the
opposite side. As a result, in the event of a blast, a short circuit in zone
1301 can cause a high
voltage to appear on circuitry in zone 1305. ,
Accordingly, at least one isolator 1303 can allow signals to pass between
zones 1305 and
1306. Any high voltage in zone 1305 can be contained in zone 1305. Note that
as the blast can
be substantially isolated from this side of the circuit board 1252, materials
that can create short
circuits will likely not be deposited in either zones 1305 or 1306. As a
result, a short will likely
CA 02709513 2010-07-14
not be created across the isolator 1303. Thus, the isolator 1303 can bridge
the division 1307 of
zones 1305 and 1306.
Fig. 49 is a perspective view illustrating an electrical switching component
according to
some inventive principles of this patent disclosure. In this embodiment, an
electrical switching
component 1310 can include a case 1311 and a connector 1316. An additional
connector 1318 is
illustrated; however, any number of connectors can be used.
The connector 1316 is disposed on a first end of the case such that the
connector 1316
can be coupled to a second connector (not illustrated) on a mounting site 1324
by moving the
case 1311 in a direction 1320. That is the connector 1316 is disposed on the
case 1311 such that
movement on direction 1320 can engage the connector 1316.
The case 1311 includes a retaining structure 1312. The retaining structure
1312 is
configured to be constrained such that movement of the case in the direction
1320 is limited. For
example, a panel 1322 of an enclosure containing the electrical switching
component 1310 can
be installed after the electrical switching component 1310 is mounted on the
mounting site 1324.
As a result, the movement of the electrical switching component 1310 is
constrained along
direction 1320. That is, the mounting site 1324 can prevent the electrical
switching component
1310 from moving in the direction of the arrow of direction 1320 while the
plate 1322 can be
configured to prevent the electrical switching component 1310 from moving in a
direction
opposite the arrow of direction 1320.
As illustrated, the retaining structure 1312 can include a protrusion
extending from a
surface of the case 1311. The plate 1322 can be disposed on a side of the
retaining structure
1312 opposite the mounting site 1324.
In another embodiment, the retaining structure 1312 can include a recessed
region within
a surface of the case 1311.- The recessed region can be configured to receive
a corresponding
tab, protrusion, or other structure of the plate 1322.
In another embodiment, the retaining structure 1312 can include mounting
locations for a
fastener. For example, a fastener can include a screw, brad, bolt, nut, or the
like. The case 1311
can include a threaded hole configured to receive a screw, for example.
Accordingly, the plate
1322 can be mounted to the case 1311 using the retaining structure 1312.
In an embodiment, the electrical switching component 1310 can include a manual
actuator 1314 coupled to an electrical switching device of the electrical
switching component
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CA 02709513 2010-07-14
1310 as described above. The manual actuator 1314 can be configured to change
a state of the
electrical switching device as the manual actuator is actuated in the
direction 1320,
Since the manual actuator 1314 can be actuated in the direction 1320, the
force applied to
actuate the manual actuator 1314 has the potential to dislodge the electrical
switching component
1310 from the mounting site 1324. However, since the retaining structure 1312
is coupled with
the plate 1322, limiting the movement along direction 1320, such actuation of
the manual
actuator 1314 can reduce a chance that the force applied will dislodge the
electrical switching
component 1310.
Fig. 50 is a cutaway view illustrating an actuator according to some inventive
principles
of this patent disclosure. The manual actuator 1314 can include an end 1334.
The end 1334 can
be configured to actuate a photointerruptor 1332. The photointerruptor 1332
can be disposed on
the circuit board 1252 described above. Accordingly, when the manual actuator
1314 is
actuated, such actuation can be sensed. In addition, the manual actuator 1314
can be configured
to move when the electrical switching device 1200 is electrically actuated.
That is, when the
electrical switching device 1200 is actuated by an electronic signal, the
electrical switching
device 1200 can cause the manual actuator 1314 to be actuated. Such actuation
can also be
sensed by the photointerruptor 1332 and interpreted as the position of the
manual actuator 1314
and hence, the state of the electrical switching device 1200. That is, from
the position, a state of
the electrical switching device can be sensed. For example, not only can an
on/off state be
sensed, but with an appropriately configured sensor, other states, such as a
tripped state can be
sensed.
In an embodiment, the manual actuator 1314 need not be present, yet the
actuation of the
electrical switching device 1200 can still be sensed. For example, the manual
actuator 1314 can
be replaced with a linkage configured to couple contacts or other structures
of the electrical
switching device 1200 to the photointerruptor 1332. Thus, the actuation can be
sensed without a
manual actuator 1314. However, in another embodiment, such linkages can
include the manual
actuator 1314.
Although a photointerruptor has been described above, other types of sensors
can be
used. For example, a mechanical contact sensor that makes or breaks an
electrical circuit can be
used. A digital position encoder can be used to sense the position of the end
1334. Any sensor
that can sense position, movement, acceleration, or the like can be used.
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CA 02709513 2010-07-14
As described above, the electrical switching component 1310 can have both high
voltage
circuitry and low voltage circuitry. In an embodiment the high voltage
circuitry can be
substantially isolated from a user. That is, a user may be required to remove
panels, cases,
enclosures, or the like beyond that used in normal operations to access the
high voltage circuitry.
Accordingly, the retaining structure 1312 can be disposed on the case 1311 to
facilitate
such isolation from a user. For example, as described above, the assembly can
have various high
voltage circuitry, conductors, or the like. Line 1336 conceptually divides the
electrical switching
component 1310 into high voltage and low voltage regions. At one end of the
electrical
switching component 1310 with the terminals 1290, high voltage circuitry is
exposed through an
opening of the case 1311. At another end of the electrical switching component
1310 with the
connectors 1316 and 1318, low voltage circuitry is exposed through the case
1311.
The retaining structure 1312 can be disposed on the case 1311 between such
openings.
Accordingly, when secured by the panel 1322 described above or other similar
structure, the high
voltage electrical circuitry and, in particular, the exposed contacts such as
the terminals 1290 of
the high voltage circuitry can be substantially isolated from a user.
Fig. 51 is a perspective view illustrating a case according to some inventive
principles of
this patent disclosure. In this embodiment, the case 1311 of the electrical
switching component
1310 includes a protrusion 1340 extending from a surface of the case 1311. The
protrusion 1340
can extend from a side of the case opposite the retaining structure 1312.
The protrusion 1340 can be aligned along the direction such that when the
protrusion is
disposed in a corresponding opening, the case is substantially constrained in
a second direction
1344 substantially orthogonal to the first direction 1320. The protrusion 1340
can be aligned
such that the case 1311 is not substantially constrained when disposed in the
corresponding
opening in direction 1320.
For example, the opening can be a slot aligned with a long axis in direction
1320. The
protrusion 1340 can have a width in direction 1344 substantially equal to the
width of the slot,
while a length of the protrusion 1340 is less than a corresponding length of
the slot in direction
1320. Thus, the electrical switching component 1310 can have a range of motion
along direction
1320 while being substantially constrained in direction 1344.
In an embodiment, the case 1311 can include a second protrusion 1342. The
second
protrusion can be disposed on the same side of the case 1311 as the first
protrusion 1340
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CA 02709513 2010-07-14
opposite the retaining structure 1312. The second protrusion 1342 can, but
need not be shaped
similarly to the first protrusion. The second protrusion 1342 can be similarly
formed to constrain
the motion of the electrical switching component 1310 when disposed in a
corresponding
opening as is the first protrusion 1340.
The first protrusion 1340 and the second protrusion 1342 can be disposed on
opposite
edges of case 1311. For example, the first protrusion 1340 can be disposed on
a first edge 1341
of the case 1311. The second protrusion 1342 can be disposed on a second edge
1343. Although
the edges 1341 and 1343 can be on the same side of the case 1311 opposite the
retaining
structure 1312, the edges 1341 and 1343 can be on opposite edges of that side.
In an embodiment, the protrusions 1340 and 1342 can be offset from each other
along
direction. 1320. That is, along the direction of insertion for mounting the
electrical switching
component 1310, the protrusions 1340 and 1342 can be offset. However, in other
embodiments,
the protrusions 1340 and 1342 need not be offset.
In an embodiment, mounting ears 1346 can be disposed on the case 1311 to mount
the
electrical switching component 1310 to a mounting location. For example, the
mounting
location can have an opening configured to receive the mounting ears 1346.
Fig. 52 is a side view illustrating the protrusion and mounting ear of Fig.
51. The
protrusion 1340 can have a height 1348 that is greater than a height 1350 of
the mounting ear
1346. Accordingly, in an embodiment, when being mounted on a mounting site,
the protrusion
1340 can contact the mounting site prior to the mounting ear 1346. As a
result, when the
protrusion 1340 is aligned with a corresponding opening, the protrusion 1340
can pass through
the opening, allowing the mounting ear 1346 to approach the mounting site.
Fig. 53 is a plan view of an. example of a mounting site for the assembly of
Fig. 51. In
this embodiment, the side of the case 1311 opposite the retaining structure
.13 12 is illustrated in
phantom. Fig. 53 illustrates a state where the electrical switching component
1310 is mounted
on the mounting site 1380, but the mounting ears 1346 are not engaged. The
mounting site 1380
includes openings 1370, 1372, and 1374. The protrusions 1340 and 1342 are
disposed in
openings 1370 and 1372, respectively. The mounting ears 1346 are disposed in
the openings
1374.
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CA 02709513 2010-07-14
As described above, the protrusions 1370 and 1372 can be higher than the
mounting ears
1346. Accordingly, when the electrical switching component 1310 is brought
into contact with
the mounting site 1380, the contact will be with the protrusions 1340 and
1342.
In an embodiment, the openings 1370 and 1372 can be longer along direction
1320 than
necessary to accommodate a range of motion of the electrical switching
component 1310 when
the mounting ears 1346 are disposed in the openings 1376. That is, a greater
amount of
misalignment of the protrusions 1340 and 1342 relative to an installed
location can be tolerated
with the openings 1370 and 1372.
Accordingly, the protrusions 1340 and 1342 can engage with the openings 1370
and 1372
with an amount of misalignment between the mounting ears 1346 and the openings
1376.
However, this does not mean that the mounting ears 1346 cannot engage the
openings as the
protrusions 1340 and 1342 can engage with the openings 1370 and 1372. If the
protrusions 1340
and 1342 engage with the openings 1370 and 1372 with the mounting ears 1346
misaligned, the
mounting ears 1346 can contact the mounting site 1380 and slide along as the
electrical
switching component 1310 is moved.
As the protrusions 1340 and 1342 are engaged with the openings 1370 and 1372,
the
motion of the electrical switching component 1310 is constrained. Thus, the
motion of the
assembly, is limited in direction 1344; however, the motion in direction 1320
is possible due to
the relative lengths of the protrusions 1340.and 1372 and the openings 1370
and 1372. The
electrical switching component 1310 can be moved along direction 1320 until
the mounting ears
1346 pass through the openings 1374. The electrical switching device 1310 can
then be moved
again along direction 1320 to engage the mounting ears 1346 with the mounting
site 1380.
Although the mounting ears 1346 have been used as an example, other mounting
structures can be used. For example, clips, hooks, or the like can be used to
mount the electrical
switching device 1310 to the mounting site 1380.
Fig. 54 illustrates an embodiment of an electrical switching module according
to some
inventive principles of this patent disclosure. In this embodiment, the module
1400 includes an
electrical switching device 1412, a controller 1414, and a communication
interface 1416, similar
to modules 1-7 described above. The electrical switching device 1412 is
coupled to line wiring
1420 and building wiring 1422 and is configured to control power to load 1418.
CA 02709513 2010-07-14
Module 1400 also includes a second electrical switching device 1424. The
second
electrical switching device 1424 is also substantially encapsulated by the
case 1410. The second
electrical switching device 1424 is coupled to line wiring 1428 and building
wiring 1430 and
configured to control power to load 1426. Although the wiring 1420 and 1428
has been
illustrated as distinct, the wirings 1420 and 1428 can be coupled together.
Furthermore, although
two electrical switching devices 1412 and 1424 have been illustrated, a module
1400 can have
any number of electrical switching devices and associated structures and
circuitry.
As illustrated, each of the electrical switching devices 1412 and 1424 are
coupled to
controller 1414. However, each electrical switching device 1412 and 1424 can
be associated
with independent circuitry. For example, each electrical switching device 1412
and 1424 can
have independent drive circuitry to actuate the electrical switching device.
Accordingly, each
electrical switching device 1412 and 1424 can be opened and closed
independently.
As described above, an electrical switching device can be coupled to a variety
of other
circuitry and components. For example, as illustrated in Fig. 2, an actuator
30 and position
sensor 32 can be coupled to the electrical switching device 12. Similarly,
each of electrical
switching devices 1412 and 1424 of Fig. 53 can have an actuator and sensor 32.
In an embodiment, the actuators of the electrical switching devices 1412 and
1424 can be
substantially independent of each other. For example, the actuators could be
placed in different
positions. Moreover, the associated position sensors can be configured to
substantially
independently sense the positions of the actuators. Although the actuators can
be independent of
one another, in an embodiment, the actuators can have some dependence. For
example, the,
actuators may be independently engaged; however, the actuators can be
structured to disengage
at substantially the same time.
Similar to the actuators, each electrical switching device 1412 and 1424 can
include other
circuitry, such as a zero-crossing detector, current and voltage sensors, or
the like. Any of the
above described circuits and/or components that are coupled to an electrical
switching device can
be coupled to one or more of the electrical switching devices 1412 and 1424.
In an embodiment, each electrical switching device 1412 and 1424 can have its
own
independent circuitry, such as the drive circuitry, detectors, sensors, or the
like described above.
However, the electrical switching devices 1412 and 1424 can have come common.
For example,
the controller 1414 can include a processor that is coupled to both the
electrical switching
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CA 02709513 2010-07-14
devices 1412 and 1424. This processor could be part of the controller 1414,
described above. In
another example, the electrical switching devices 1412 and 1424 can share a
common power
supply. That is, from one or more of the line wirings 1420 and 1428, a power
supply can be
generated for us in the electronics of the module 1400. In yet another
example, the power supply
could be received from outside of the module 1400 and similarly used for
circuitry of both
electrical switching devices 1412 and 1424. In another example, a common
circuit board can be
used for the electrical switching devices 1412 and 1424.
In an embodiment; the electrical switching devices 1412 and 1424 can be
substantially
encapsulated in different chambers. As illustrated, electrical switching
device 1412 is
substantially encapsulated in chamber 1432. Similarly, electrical switching
devices 1424 is
substantially encapsulated in chamber 1434. Bulkheads 1436, 1436, 1440, or the
like, such as
the bulkheads described above, can define the chambers 1432 and 1434, and
substantially isolate
the electrical switching devices 1412 and 1424. As a result, a failure in one
electrical switching
device can have a reduced impact on other electrical switching devices in the
module.
Moreover, the inventive principles of this patent disclosure have been
described above
with reference to some specific example embodiments, but these embodiments can
be modified
in arrangement and detail without departing from the inventive concepts. Such
changes and
modifications are considered to fall within the scope of the following claims.
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